diff --git a/README.md b/README.md
index 26586ce..fef757e 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,7 @@ block-opening-brace-space-before=error
 double-semicolon=error
 double-spaces=error
 ellipsis=error
+indentation=error
 line-length=warn
 naming-convention=error
 no-space=error
@@ -89,6 +90,9 @@ unnecessary-string-template=error
 [Disabler]
 disable-by-inline-comments=true
 
+[indentation]
+indent-size=4
+
 [line-length]
 max-line-length=120
 ignore-comments=true
diff --git a/lib/Checks/IndentationCheck.vala b/lib/Checks/IndentationCheck.vala
new file mode 100644
index 0000000..ca8a8e7
--- /dev/null
+++ b/lib/Checks/IndentationCheck.vala
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2019 elementary LLC. (https://github.com/elementary/vala-lint)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ */
+
+public class ValaLint.Checks.IndentationCheck : Check {
+    const string MESSAGE = _("Indentation is %d but should %d");
+    public int indent_size;
+
+    public IndentationCheck () {
+        Object (
+            title: _("indentation"),
+            description: _("Checks for correct indentation")
+        );
+
+        state = Config.get_state (title);
+        indent_size = Config.get_integer (title, "indent-size");
+    }
+
+    public override void check (Vala.ArrayList<ParseResult?> parse_result,
+                                ref Vala.ArrayList<FormatMistake?> mistake_list) {
+
+    }
+
+    public bool is_node_in_namespace (Vala.CodeNode n, Vala.Namespace ns) {
+        if (n is Vala.Class) {
+            return ns.get_classes ().contains ((Vala.Class)n);
+        } else if (n is Vala.Interface) {
+            return ns.get_interfaces ().contains ((Vala.Interface)n);
+        } else if (n is Vala.Struct) {
+            return ns.get_structs ().contains ((Vala.Struct)n);
+        } else if (n is Vala.Enum) {
+            return ns.get_enums ().contains ((Vala.Enum)n);
+        } else if (n is Vala.ErrorDomain) {
+            return ns.get_error_domains ().contains ((Vala.ErrorDomain)n);
+        } else if (n is Vala.Delegate) {
+            return ns.get_delegates ().contains ((Vala.Delegate)n);
+        } else if (n is Vala.Constant) {
+            return ns.get_constants ().contains ((Vala.Constant)n);
+        } else if (n is Vala.Field) {
+            return ns.get_fields ().contains ((Vala.Field)n);
+        } else if (n is Vala.Method) {
+            return ns.get_methods ().contains ((Vala.Method)n);
+        } else if (n is Vala.Namespace) {
+            return ns.get_namespaces ().contains ((Vala.Namespace)n);
+        }
+
+        return false;
+    }
+
+    public bool is_explicit_namespace (Vala.Namespace ns) {
+        foreach (var n in ns.get_classes ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_interfaces ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_structs ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_enums ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_error_domains ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_delegates ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_constants ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_fields ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_methods ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        foreach (var n in ns.get_namespaces ()) {
+            if (n.source_reference.begin.line == ns.source_reference.begin.line) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public bool is_else_if_statement (Vala.IfStatement s) {
+        var b = s.parent_node;
+        if (b != null && b.parent_node is Vala.IfStatement) {
+            Vala.IfStatement if_statement = (Vala.IfStatement)b.parent_node;
+            if (if_statement.false_statement == b && b.source_reference.begin.line == s.source_reference.begin.line) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    public void check_block (Vala.Block b, int level, ref Vala.ArrayList<FormatMistake?> mistake_list) {
+        if (state == Config.State.OFF) {
+            return;
+        }
+
+        foreach (var s in b.get_statements ()) {
+            int offset = 0;
+
+            if (s is Vala.IfStatement && is_else_if_statement ((Vala.IfStatement)s)) {
+                offset -= 1;
+            }
+
+            var n = b.parent_node;
+            while (n != null) {
+                if (n is Vala.LockStatement) {
+                    offset += 1;
+                }
+
+                n = n.parent_node;
+            }
+
+            if (s.parent_node == null || s.parent_node.source_reference.begin.line != s.source_reference.begin.line) {
+                check_line (s.source_reference, level + offset, ref mistake_list);
+            }
+        }
+    }
+
+    public void check_symbol (Vala.Symbol s, int level, ref Vala.ArrayList<FormatMistake?> mistake_list) {
+        if (state == Config.State.OFF) {
+            return;
+        }
+
+        if (s.parent_node == null || s.parent_node.source_reference.begin.line != s.source_reference.begin.line) {
+            check_line (s.source_reference, level, ref mistake_list);
+        }
+    }
+
+    private void check_line (Vala.SourceReference loc, int level, ref Vala.ArrayList<FormatMistake?> mistake_list) {
+        Vala.SourceLocation line = loc.begin;
+        char* file_begin = loc.file.get_mapped_contents ();
+
+        while (line.pos > file_begin && line.pos[0] != '\n') {
+            line.pos -= 1;
+            line.column -= 1;
+        }
+
+        var first_char = line;
+        int indent = 0;
+        while (first_char.pos[0] == ' ' || first_char.pos[0] == '\n' || first_char.pos[0] == '\t') {
+            if (first_char.pos[0] == ' ') {
+                indent += 1;
+            }
+
+            first_char.pos += 1;
+            first_char.column += 1;
+        }
+
+        int indent_should = level * indent_size;
+        if (indent != indent_should) {
+            add_mistake ({ this, first_char, line, MESSAGE.printf (indent, indent_should) }, ref mistake_list);
+        }
+    }
+}
diff --git a/lib/Config.vala b/lib/Config.vala
index 198b036..63aa7d7 100644
--- a/lib/Config.vala
+++ b/lib/Config.vala
@@ -48,6 +48,7 @@ public class ValaLint.Config {
         default_config.set_string ("Checks", "double-semicolon", State.ERROR.to_string ());
         default_config.set_string ("Checks", "double-spaces", State.ERROR.to_string ());
         default_config.set_string ("Checks", "ellipsis", State.ERROR.to_string ());
+        default_config.set_string ("Checks", "indentation", State.ERROR.to_string ());
         default_config.set_string ("Checks", "line-length", State.WARN.to_string ());
         default_config.set_string ("Checks", "naming-convention", State.ERROR.to_string ());
         default_config.set_string ("Checks", "no-space", State.ERROR.to_string ());
@@ -60,6 +61,8 @@ public class ValaLint.Config {
 
         default_config.set_boolean ("Disabler", "disable-by-inline-comments", true);
 
+        default_config.set_integer ("indentation", "indent-size", 4);
+
         default_config.set_double ("line-length", "max-line-length", 120);
         default_config.set_boolean ("line-length", "ignore-comments", true);
 
diff --git a/lib/Linter.vala b/lib/Linter.vala
index f11e1f7..2a9c6ae 100644
--- a/lib/Linter.vala
+++ b/lib/Linter.vala
@@ -47,6 +47,7 @@ public class ValaLint.Linter : Object {
 
         visitor = new ValaLint.Visitor ();
         visitor.double_semicolon_check = new Checks.DoubleSemicolonCheck ();
+        visitor.indentation_check = new Checks.IndentationCheck ();
         visitor.ellipsis_check = new Checks.EllipsisCheck ();
         visitor.naming_convention_check = new Checks.NamingConventionCheck ();
         visitor.no_space_check = new Checks.NoSpaceCheck ();
diff --git a/lib/ValaVisitor.vala b/lib/ValaVisitor.vala
index a1ceff1..c6231b0 100644
--- a/lib/ValaVisitor.vala
+++ b/lib/ValaVisitor.vala
@@ -18,9 +18,12 @@
  */
 
 class ValaLint.Visitor : Vala.CodeVisitor {
+    private int level = 0;
+
     public Vala.ArrayList<FormatMistake?> mistake_list;
 
     public Checks.DoubleSemicolonCheck double_semicolon_check;
+    public Checks.IndentationCheck indentation_check;
     public Checks.EllipsisCheck ellipsis_check;
     public Checks.NamingConventionCheck naming_convention_check;
     public Checks.UnnecessaryStringTemplateCheck unnecessary_string_template_check;
@@ -31,43 +34,84 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_source_file (Vala.SourceFile sf) {
-        sf.accept_children (this);
+        // Filter nodes which are already visited via Vala.Namespace
+        foreach (var node in sf.get_nodes ()) {
+            bool visit = true;
+
+            foreach (var ns in sf.get_nodes ()) {
+                if (ns is Vala.Namespace && indentation_check.is_node_in_namespace (node, (Vala.Namespace)ns)) {
+                    visit = false;
+                    break;
+                }
+            }
+
+            //  print ("asdf: %d %d\n", node.source_reference.begin.line, (int)visit);
+            if (visit) {
+                node.accept (this);
+            }
+        }
     }
 
     public override void visit_namespace (Vala.Namespace ns) {
         /* namespace name may be null */
+        indentation_check.check_symbol (ns, level, ref mistake_list);
         naming_convention_check.check_camel_case (ns, ref mistake_list);
 
+        int indent = indentation_check.is_explicit_namespace (ns) ? 1 : 0;
+        level += indent;
         ns.accept_children (this);
+        level -= indent;
     }
 
     public override void visit_class (Vala.Class cl) {
+        indentation_check.check_symbol (cl, level, ref mistake_list);
         naming_convention_check.check_camel_case (cl, ref mistake_list);
+
+        level += 1;
         cl.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_struct (Vala.Struct st) {
+        indentation_check.check_symbol (st, level, ref mistake_list);
         naming_convention_check.check_camel_case (st, ref mistake_list);
+
+        level += 1;
         st.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_interface (Vala.Interface iface) {
+        indentation_check.check_symbol (iface, level, ref mistake_list);
         naming_convention_check.check_camel_case (iface, ref mistake_list);
+
+        level += 1;
         iface.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_enum (Vala.Enum en) {
+        indentation_check.check_symbol (en, level, ref mistake_list);
         naming_convention_check.check_camel_case (en, ref mistake_list);
+
+        level += 1;
         en.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_enum_value (Vala.EnumValue ev) {
+        indentation_check.check_symbol (ev, level, ref mistake_list);
         naming_convention_check.check_all_caps (ev, ref mistake_list);
         ev.accept_children (this);
     }
 
     public override void visit_error_domain (Vala.ErrorDomain edomain) {
+        indentation_check.check_symbol (edomain, level, ref mistake_list);
+        naming_convention_check.check_camel_case (edomain, ref mistake_list);
+
+        level += 1;
         edomain.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_error_code (Vala.ErrorCode ecode) {
@@ -75,37 +119,41 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_delegate (Vala.Delegate d) {
+        indentation_check.check_symbol (d, level, ref mistake_list);
         d.accept_children (this);
     }
 
     public override void visit_constant (Vala.Constant c) {
+        double_semicolon_check.check_statement (c, ref mistake_list);
+        indentation_check.check_symbol (c, level, ref mistake_list);
         naming_convention_check.check_all_caps (c, ref mistake_list);
 
         c.accept_children (this);
     }
 
     public override void visit_field (Vala.Field f) {
+        double_semicolon_check.check_statement (f, ref mistake_list);
+        indentation_check.check_symbol (f, level, ref mistake_list);
         naming_convention_check.check_underscore (f, ref mistake_list);
 
         f.accept_children (this);
     }
 
     public override void visit_method (Vala.Method m) {
-        /* method name may be null */
+        /* Method name may be null */
+        indentation_check.check_symbol (m, level, ref mistake_list);
         naming_convention_check.check_underscore (m, ref mistake_list);
-
         no_space_check.check_list (m.get_parameters (), ref mistake_list);
 
-        /* Error types depend on the vala version. */
-        //  var error_types = new Vala.ArrayList<Vala.DataType?> ();
-        //  m.get_error_types (error_types);
-        //  no_space_check.check_list (error_types, ref mistake_list);
-
+        level += 1;
         m.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_creation_method (Vala.CreationMethod m) {
+        level += 1;
         m.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_formal_parameter (Vala.Parameter p) {
@@ -115,23 +163,39 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_property (Vala.Property prop) {
+        indentation_check.check_symbol (prop, level, ref mistake_list);
+
+        level += 1;
         prop.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_property_accessor (Vala.PropertyAccessor acc) {
+        level += 1;
         acc.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_signal (Vala.Signal sig) {
+        indentation_check.check_symbol (sig, level, ref mistake_list);
+
         sig.accept_children (this);
     }
 
     public override void visit_constructor (Vala.Constructor c) {
+        indentation_check.check_symbol (c, level, ref mistake_list);
+
+        level += 1;
         c.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_destructor (Vala.Destructor d) {
+        indentation_check.check_symbol (d, level, ref mistake_list);
+
+        level += 1;
         d.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_type_parameter (Vala.TypeParameter p) {
@@ -147,6 +211,8 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_block (Vala.Block b) {
+        indentation_check.check_block (b, level, ref mistake_list);
+
         b.accept_children (this);
     }
 
@@ -168,7 +234,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     public override void visit_initializer_list (Vala.InitializerList list) {
         no_space_check.check_list (list.get_initializers (), ref mistake_list);
 
+        level += 1;
         list.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_expression_statement (Vala.ExpressionStatement stmt) {
@@ -178,7 +246,10 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_if_statement (Vala.IfStatement stmt) {
+        int level_indent = indentation_check.is_else_if_statement (stmt) ? 0 : 1;
+        level += level_indent;
         stmt.accept_children (this);
+        level -= level_indent;
     }
 
     public override void visit_switch_statement (Vala.SwitchStatement stmt) {
@@ -186,7 +257,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_switch_section (Vala.SwitchSection section) {
+        level += 1;
         section.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_switch_label (Vala.SwitchLabel label) {
@@ -198,19 +271,27 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_while_statement (Vala.WhileStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_do_statement (Vala.DoStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_for_statement (Vala.ForStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_foreach_statement (Vala.ForeachStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_break_statement (Vala.BreakStatement stmt) {
@@ -240,7 +321,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_try_statement (Vala.TryStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_catch_clause (Vala.CatchClause clause) {
@@ -248,7 +331,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_lock_statement (Vala.LockStatement stmt) {
+        level += 1;
         stmt.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_unlock_statement (Vala.UnlockStatement stmt) {
@@ -301,7 +386,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     public override void visit_tuple (Vala.Tuple tuple) {
         no_space_check.check_list (tuple.get_expressions (), ref mistake_list);
 
+        level += 1;
         tuple.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_null_literal (Vala.NullLiteral lit) {
@@ -315,7 +402,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     public override void visit_method_call (Vala.MethodCall expr) {
         no_space_check.check_list (expr.get_argument_list (), ref mistake_list);
 
+        level += 1;
         expr.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_element_access (Vala.ElementAccess expr) {
@@ -335,7 +424,9 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_object_creation_expression (Vala.ObjectCreationExpression expr) {
+        level += 1;
         expr.accept_children (this);
+        level -= 1;
     }
 
     public override void visit_sizeof_expression (Vala.SizeofExpression expr) {
@@ -387,7 +478,11 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     public override void visit_lambda_expression (Vala.LambdaExpression expr) {
         no_space_check.check_list (expr.get_parameters (), ref mistake_list);
 
+        bool parent_on_same_line = (expr.source_reference.begin.line != expr.parent_node.source_reference.begin.line);
+        int indent = (expr.statement_body != null && parent_on_same_line) ? 1 : 0;
+        level += indent;
         expr.accept_children (this);
+        level -= indent;
     }
 
     public override void visit_assignment (Vala.Assignment a) {
diff --git a/lib/meson.build b/lib/meson.build
index 7aa747b..c1495af 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -13,6 +13,7 @@ vala_linter_files = files(
     'Checks/DoubleSemicolonCheck.vala',
     'Checks/DoubleSpacesCheck.vala',
     'Checks/EllipsisCheck.vala',
+    'Checks/IndentationCheck.vala',
     'Checks/LineLengthCheck.vala',
     'Checks/NamingConventionCheck.vala',
     'Checks/NoSpaceCheck.vala',
diff --git a/test/FileTest.vala b/test/FileTest.vala
index 0da7e18..f3d1eef 100644
--- a/test/FileTest.vala
+++ b/test/FileTest.vala
@@ -56,6 +56,7 @@ class FileTest : GLib.Object {
         int line = 0; // So that new tests can be added without changing every number...
         var m_warnings = new Vala.ArrayList<FileTestMistake?> ();
         m_warnings.add ({ "naming-convention", line += 4 });
+        m_warnings.add ({ "indentation", line += 1 });
         m_warnings.add ({ "space-before-paren", line += 2 });
         m_warnings.add ({ "note", line += 1, "TODO" });
         m_warnings.add ({ "note", line += 1, "TODO: Lorem ipsum" });
@@ -76,7 +77,8 @@ class FileTest : GLib.Object {
         m_warnings.add ({ "unnecessary-string-template", line += 1 });
         m_warnings.add ({ "line-length", line += 2 });
         m_warnings.add ({ "line-length", line += 1 });
-        m_warnings.add ({ "trailing-newlines", line += 2 });
+        m_warnings.add ({ "indentation", line += 3 });
+        m_warnings.add ({ "trailing-newlines", line += 3 });
 
         check_file_for_mistake (File.new_for_path ("../test/files/warnings.vala"), m_warnings);
 
diff --git a/test/files/pass.vala b/test/files/pass.vala
index c644d6d..8d94b49 100644
--- a/test/files/pass.vala
+++ b/test/files/pass.vala
@@ -1,4 +1,20 @@
-class FileTest : GLib.Object {
+namespace NamespaceName {
+    class Test {
+        int a;
+    }
+}
+
+class TestNamespace.FileTest : GLib.Object {
+
+    // Property for indentation
+    public int test { get { return this._number; }; set; }
+    public int number { get {
+            return this._number;
+        }
+        set {
+            this._number = value;
+        }
+    }
 
     public static int main (string[] args) {
         string no_ellipsis = ".. lorem ipsum."; // This is a very long comment over the line-length limit of 120 characters...
@@ -8,6 +24,56 @@ class FileTest : GLib.Object {
         string literal = "Lorem ipsum";
         var string_template = @"$literal et al.";
 
+        // Some checks for indentation
+        if (true) {
+            var b = 3;
+        } else {
+            if (true) {
+                var a = 2;
+
+                switch (a) {
+                case 2: {
+                    a = 3;
+                    break;
+                }
+
+                default:
+                    break;
+                }
+            }
+        }
+
+        Bus.own_name (BusType.SESSION, "org.pantheon.greeter", BusNameOwnerFlags.NONE,
+            (connection) => {
+                if (instance == null) {
+                    instance = new DBus ();
+                }
+
+                try {
+                    connection.register_object ("/org/pantheon/greeter", instance);
+                } catch (Error e) {
+                    warning (e.message);
+                }
+            },
+            () => {},
+            () => warning ("Could not acquire name\n")
+        );
+
+        lock (notifications) {
+            notifications = null;
+        }
+
+        new Thread<void*> (null, () => {
+            lock (notifications) {
+                try {
+                    notifications = connection.get_proxy_sync<DBusNotifications> ("org.freedesktop.Notifications",
+                        "/org/freedesktop/Notifications", DBusProxyFlags.NONE);
+                } catch (Error e) {
+                    notifications = null;
+                }
+            }
+            return null;
+        });
         var /* comment */ string_double_space = /* */ "lorem";
 
         return 0;
diff --git a/test/files/warnings.vala b/test/files/warnings.vala
index bbff8c6..b827684 100644
--- a/test/files/warnings.vala
+++ b/test/files/warnings.vala
@@ -2,6 +2,7 @@
 
 class FileTest : GLib.Object {
     const int underscore_constant = 3;
+        int wrong_indentation;
 
     public static int main(string[] args) {
         test (); // TODO
@@ -26,5 +27,9 @@ class FileTest : GLib.Object {
 
         string this_is_a_very_long_variable_name_to_get_over_the_120_character_line_length_limit = "lorem ipsum dolor amet test"; // despite the comment
         string this_is_a_very_long_variable_name_to_get_over_the_120_character_line_with_comment /* with comment */ = "lorem ipsum dolor amet test"; // and comment here
+
+        if (empty_string_template == "") {
+                wrong_indentation = 3;
+        }
     }
 }
\ No newline at end of file
diff --git a/vala-lint.conf b/vala-lint.conf
index 63a96e0..ac6c14f 100644
--- a/vala-lint.conf
+++ b/vala-lint.conf
@@ -3,6 +3,7 @@ block-opening-brace-space-before=error
 double-semicolon=error
 double-spaces=error
 ellipsis=error
+indentation=error
 line-length=warn
 naming-convention=error
 no-space=error
@@ -16,6 +17,9 @@ unnecessary-string-template=error
 [Disabler]
 disable-by-inline-comments=true
 
+[indentation]
+indent-size=4
+
 [line-length]
 max-line-length=120
 ignore-comments=true