diff --git a/Processor.php b/Processor.php
index 6dc208f..2b8988e 100644
--- a/Processor.php
+++ b/Processor.php
@@ -99,7 +99,17 @@ private function processParams(array $config, array $expectedParams, array $actu
             $actualParams = array_intersect_key($actualParams, $expectedParams);
         }
 
-        $envMap = empty($config['env-map']) ? array() : (array) $config['env-map'];
+        $envMap = array();
+        if (!empty($config['env-map'])) {
+            if ('auto' === $config['env-map']) {
+                $envPrefix = !empty($config['env-prefix']) ? $config['env-prefix'] : '';
+                foreach ($expectedParams as $key => $value) {
+                    $envMap[$key] = $envPrefix.strtoupper(str_replace('.', '__', $key));
+                }
+            } else {
+                $envMap = (array)$config['env-map'];
+            }
+        }
 
         // Add the params coming from the environment values
         $actualParams = array_replace($actualParams, $this->getEnvValues($envMap));
diff --git a/Tests/fixtures/testcases/environment_auto/dist.yml b/Tests/fixtures/testcases/environment_auto/dist.yml
new file mode 100644
index 0000000..72e554a
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto/dist.yml
@@ -0,0 +1,6 @@
+parameters:
+    boolean: false
+    another: ~
+    nested: nested
+    foo_baz: ''
+    foo.baz: ''
diff --git a/Tests/fixtures/testcases/environment_auto/expected.yml b/Tests/fixtures/testcases/environment_auto/expected.yml
new file mode 100644
index 0000000..7164a11
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto/expected.yml
@@ -0,0 +1,12 @@
+# This file is auto-generated during the composer install
+parameters:
+    boolean: true
+    another: null
+    nested:
+        foo: env_foo
+        bar:
+            - env
+            - test
+            - null
+    foo_baz: foo_baz
+    foo.baz: foo.baz
diff --git a/Tests/fixtures/testcases/environment_auto/setup.yml b/Tests/fixtures/testcases/environment_auto/setup.yml
new file mode 100644
index 0000000..811f016
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto/setup.yml
@@ -0,0 +1,10 @@
+title: Automatically mapped values provided by the environment
+
+config:
+    env-map: 'auto'
+
+environment:
+    BOOLEAN: 'true'
+    FOO_BAZ: 'foo_baz'
+    FOO__BAZ: 'foo.baz'
+    NESTED: '{foo: env_foo, bar: [env, test, null]}'
diff --git a/Tests/fixtures/testcases/environment_auto_with_prefix/dist.yml b/Tests/fixtures/testcases/environment_auto_with_prefix/dist.yml
new file mode 100644
index 0000000..72e554a
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto_with_prefix/dist.yml
@@ -0,0 +1,6 @@
+parameters:
+    boolean: false
+    another: ~
+    nested: nested
+    foo_baz: ''
+    foo.baz: ''
diff --git a/Tests/fixtures/testcases/environment_auto_with_prefix/expected.yml b/Tests/fixtures/testcases/environment_auto_with_prefix/expected.yml
new file mode 100644
index 0000000..7164a11
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto_with_prefix/expected.yml
@@ -0,0 +1,12 @@
+# This file is auto-generated during the composer install
+parameters:
+    boolean: true
+    another: null
+    nested:
+        foo: env_foo
+        bar:
+            - env
+            - test
+            - null
+    foo_baz: foo_baz
+    foo.baz: foo.baz
diff --git a/Tests/fixtures/testcases/environment_auto_with_prefix/setup.yml b/Tests/fixtures/testcases/environment_auto_with_prefix/setup.yml
new file mode 100644
index 0000000..b10829d
--- /dev/null
+++ b/Tests/fixtures/testcases/environment_auto_with_prefix/setup.yml
@@ -0,0 +1,11 @@
+title: Automatically mapped values provided by the environment with configured prefix
+
+config:
+    env-map: 'auto'
+    env-prefix: 'SYMFONY__'
+
+environment:
+    SYMFONY__BOOLEAN: 'true'
+    SYMFONY__FOO_BAZ: 'foo_baz'
+    SYMFONY__FOO__BAZ: 'foo.baz'
+    SYMFONY__NESTED: '{foo: env_foo, bar: [env, test, null]}'