diff --git a/docs/generators/kotlin-server-deprecated.md b/docs/generators/kotlin-server-deprecated.md
index 5499354747c..aa33465abdd 100644
--- a/docs/generators/kotlin-server-deprecated.md
+++ b/docs/generators/kotlin-server-deprecated.md
@@ -80,15 +80,18 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>continue</li>
 <li>do</li>
 <li>else</li>
+<li>external</li>
 <li>false</li>
 <li>for</li>
 <li>fun</li>
 <li>if</li>
 <li>in</li>
 <li>interface</li>
+<li>internal</li>
 <li>is</li>
 <li>null</li>
 <li>object</li>
+<li>open</li>
 <li>package</li>
 <li>return</li>
 <li>super</li>
diff --git a/docs/generators/kotlin-server.md b/docs/generators/kotlin-server.md
index 7d9beb5ae10..4ea1d39a6ee 100644
--- a/docs/generators/kotlin-server.md
+++ b/docs/generators/kotlin-server.md
@@ -82,15 +82,18 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>continue</li>
 <li>do</li>
 <li>else</li>
+<li>external</li>
 <li>false</li>
 <li>for</li>
 <li>fun</li>
 <li>if</li>
 <li>in</li>
 <li>interface</li>
+<li>internal</li>
 <li>is</li>
 <li>null</li>
 <li>object</li>
+<li>open</li>
 <li>package</li>
 <li>return</li>
 <li>super</li>
diff --git a/docs/generators/kotlin-spring.md b/docs/generators/kotlin-spring.md
index 3c62035e71e..e2895ecc57f 100644
--- a/docs/generators/kotlin-spring.md
+++ b/docs/generators/kotlin-spring.md
@@ -93,15 +93,18 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>continue</li>
 <li>do</li>
 <li>else</li>
+<li>external</li>
 <li>false</li>
 <li>for</li>
 <li>fun</li>
 <li>if</li>
 <li>in</li>
 <li>interface</li>
+<li>internal</li>
 <li>is</li>
 <li>null</li>
 <li>object</li>
+<li>open</li>
 <li>package</li>
 <li>return</li>
 <li>super</li>
diff --git a/docs/generators/kotlin-vertx.md b/docs/generators/kotlin-vertx.md
index f92dadaf520..2d0fb923d13 100644
--- a/docs/generators/kotlin-vertx.md
+++ b/docs/generators/kotlin-vertx.md
@@ -74,15 +74,18 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>continue</li>
 <li>do</li>
 <li>else</li>
+<li>external</li>
 <li>false</li>
 <li>for</li>
 <li>fun</li>
 <li>if</li>
 <li>in</li>
 <li>interface</li>
+<li>internal</li>
 <li>is</li>
 <li>null</li>
 <li>object</li>
+<li>open</li>
 <li>package</li>
 <li>return</li>
 <li>super</li>
diff --git a/docs/generators/kotlin.md b/docs/generators/kotlin.md
index 6432fc5be67..5883c0f573e 100644
--- a/docs/generators/kotlin.md
+++ b/docs/generators/kotlin.md
@@ -84,15 +84,18 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>continue</li>
 <li>do</li>
 <li>else</li>
+<li>external</li>
 <li>false</li>
 <li>for</li>
 <li>fun</li>
 <li>if</li>
 <li>in</li>
 <li>interface</li>
+<li>internal</li>
 <li>is</li>
 <li>null</li>
 <li>object</li>
+<li>open</li>
 <li>package</li>
 <li>return</li>
 <li>super</li>
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
index c681aaf51cb..8905d13a3f7 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
@@ -125,7 +125,10 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
                 "val",
                 "var",
                 "when",
-                "while"
+                "while",
+                "open",
+                "external",
+                "internal"
         ));
 
         defaultIncludes = new HashSet<String>(Arrays.asList(
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/KotlinReservedWordsTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/KotlinReservedWordsTest.java
index 58727aa3803..914ed814da8 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/KotlinReservedWordsTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/KotlinReservedWordsTest.java
@@ -48,7 +48,10 @@ public class KotlinReservedWordsTest {
                 {"val"},
                 {"var"},
                 {"when"},
-                {"while"}
+                {"while"},
+                {"open"},
+                {"external"},
+                {"internal"}
         };
     }
 
diff --git a/modules/openapi-generator/src/test/resources/3_0/kotlin/reserved_words.yaml b/modules/openapi-generator/src/test/resources/3_0/kotlin/reserved_words.yaml
index c4022711783..881ffe49499 100644
--- a/modules/openapi-generator/src/test/resources/3_0/kotlin/reserved_words.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/kotlin/reserved_words.yaml
@@ -120,6 +120,18 @@ paths:
           in: header
           schema:
             type: string
+        - name: open
+          in: header
+          schema:
+            type: string
+        - name: external
+          in: header
+          schema:
+            type: string
+        - name: internal
+          in: header
+          schema:
+            type: string
       responses:
         '200':
           $ref: "#/components/schemas/Good"
@@ -186,6 +198,12 @@ components:
           type: string
         while:
           type: string
+        open:
+          type: string
+        external:
+          type: string
+        internal:
+          type: string
         linked:
           $ref: '#/components/schemas/Linked'
 
@@ -249,7 +267,12 @@ components:
           $ref: '#/components/schemas/when'
         while:
           $ref: '#/components/schemas/while'
-
+        open:
+          $ref: '#/components/schemas/open'
+        external:
+          $ref: '#/components/schemas/external'
+        internal:
+          $ref: '#/components/schemas/internal'
     as:
       title: Testing reserved word 'as'
       type: object
@@ -469,6 +492,30 @@ components:
     while:
       title: Testing reserved word 'while'
       type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+
+    open:
+      title: Testing reserved word 'open'
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+
+    external:
+      title: Testing reserved word 'external'
+      type: object
+      properties:
+        id:
+          type: integer
+          format: int64
+
+    internal:
+      title: Testing reserved word 'internal'
+      type: object
       properties:
         id:
           type: integer