diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/StringUtils.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/StringUtils.java
index 9bca83d638bb..9ad3082b8828 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/StringUtils.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/StringUtils.java
@@ -117,8 +117,7 @@ public static String camelize(String word) {
 
     private static Pattern camelizeSlashPattern = Pattern.compile("\\/(.?)");
     private static Pattern camelizeUppercasePattern = Pattern.compile("(\\.?)(\\w)([^\\.]*)$");
-    private static Pattern camelizeUnderscorePattern = Pattern.compile("(_)(.)");
-    private static Pattern camelizeHyphenPattern = Pattern.compile("(-)(.)");
+    private static Pattern camelizeCharsPattern = Pattern.compile("([_ -])(.)");
     private static Pattern camelizeDollarPattern = Pattern.compile("\\$");
     private static Pattern camelizeSimpleUnderscorePattern = Pattern.compile("_");
 
@@ -167,7 +166,8 @@ public static String camelize(final String inputWord, boolean lowercaseFirstLett
             }
 
             // Remove all underscores (underscore_case to camelCase)
-            m = camelizeUnderscorePattern.matcher(word);
+            // Remove all hyphens (hyphen-case to camelCase)
+            m = camelizeCharsPattern.matcher(word);
             while (m.find()) {
                 String original = m.group(2);
                 String upperCase = original.toUpperCase(Locale.ROOT);
@@ -176,14 +176,7 @@ public static String camelize(final String inputWord, boolean lowercaseFirstLett
                 } else {
                     word = m.replaceFirst(upperCase);
                 }
-                m = camelizeUnderscorePattern.matcher(word);
-            }
-
-            // Remove all hyphens (hyphen-case to camelCase)
-            m = camelizeHyphenPattern.matcher(word);
-            while (m.find()) {
-                word = m.replaceFirst(m.group(2).toUpperCase(Locale.ROOT));
-                m = camelizeHyphenPattern.matcher(word);
+                m = camelizeCharsPattern.matcher(word);
             }
 
             if (lowerFirstLetter && word.length() > 0) {
@@ -266,9 +259,9 @@ public static String escape(final String name, final Map<String, String> replace
                     return character;
                 }
             }).reduce( (c1, c2) -> "" + c1 + c2).orElse(null);
-    
+
             if (result != null) return result;
-            throw new RuntimeException("Word '" + name + "' could not be escaped.");    
+            throw new RuntimeException("Word '" + name + "' could not be escaped.");
         });
     }
 }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/StringUtilsTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/StringUtilsTest.java
index d4a8efebae59..b554080591f7 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/StringUtilsTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/StringUtilsTest.java
@@ -19,12 +19,18 @@ public void testCamelize() throws Exception {
         Assert.assertEquals(camelize("some-value"), "SomeValue");
         Assert.assertEquals(camelize("some_value"), "SomeValue");
         Assert.assertEquals(camelize("$type"), "$Type");
+        Assert.assertEquals(camelize("Upper lower"), "UpperLower");
+        Assert.assertEquals(camelize("Upper Upper"), "UpperUpper");
+        Assert.assertEquals(camelize("lower Upper"), "LowerUpper");
 
         Assert.assertEquals(camelize("abcd", true), "abcd");
         Assert.assertEquals(camelize("some-value", true), "someValue");
         Assert.assertEquals(camelize("some_value", true), "someValue");
         Assert.assertEquals(camelize("Abcd", true), "abcd");
         Assert.assertEquals(camelize("$type", true), "$type");
+        Assert.assertEquals(camelize("Upper lower", true), "upperLower");
+        Assert.assertEquals(camelize("Upper Upper", true), "upperUpper");
+        Assert.assertEquals(camelize("lower Upper", true), "lowerUpper");
 
         Assert.assertEquals(camelize("123", true), "123");
         Assert.assertEquals(camelize("$123", true), "$123");