diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
index 4b74d10686d..10cfdd80cc1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
@@ -629,6 +629,9 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
         } else if (ModelUtils.isMapSchema(p)) {
             Schema<?> inner = getSchemaAdditionalProperties(p);
             String nullSafeSuffix = getNullSafeAdditionalProps() ? " | undefined" : "";
+            if (Boolean.TRUE.equals(inner.getNullable())) {
+                nullSafeSuffix += " | null";
+            }
             return "{ [key: string]: " + getTypeDeclaration(unaliasSchema(inner)) + nullSafeSuffix + "; }";
         } else if (ModelUtils.isFileSchema(p)) {
             return "File";
diff --git a/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts b/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
index a2119d89b14..795071edc3c 100644
--- a/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
+++ b/samples/client/petstore/typescript-axios/builds/test-petstore/api.ts
@@ -1107,16 +1107,16 @@ export interface NullableClass {
     'object_nullable_prop'?: { [key: string]: object; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    'object_and_items_nullable_prop'?: { [key: string]: object; } | null;
+    'object_and_items_nullable_prop'?: { [key: string]: object | null; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    'object_items_nullable'?: { [key: string]: object; };
+    'object_items_nullable'?: { [key: string]: object | null; };
 }
 /**
  * @type NullableShape
diff --git a/samples/client/petstore/typescript-axios/builds/with-fake-endpoints-models-for-testing-with-http-signature/api.ts b/samples/client/petstore/typescript-axios/builds/with-fake-endpoints-models-for-testing-with-http-signature/api.ts
index 2c8551e9254..cbfc7da19ad 100644
--- a/samples/client/petstore/typescript-axios/builds/with-fake-endpoints-models-for-testing-with-http-signature/api.ts
+++ b/samples/client/petstore/typescript-axios/builds/with-fake-endpoints-models-for-testing-with-http-signature/api.ts
@@ -875,16 +875,16 @@ export interface NullableClass {
     'object_nullable_prop'?: { [key: string]: object; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    'object_and_items_nullable_prop'?: { [key: string]: object; } | null;
+    'object_and_items_nullable_prop'?: { [key: string]: object | null; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    'object_items_nullable'?: { [key: string]: object; };
+    'object_items_nullable'?: { [key: string]: object | null; };
 }
 /**
  * 
diff --git a/samples/client/petstore/typescript-fetch/builds/default-v3.0/models/NullableClass.ts b/samples/client/petstore/typescript-fetch/builds/default-v3.0/models/NullableClass.ts
index 94b8e43e6f5..52e1a217164 100644
--- a/samples/client/petstore/typescript-fetch/builds/default-v3.0/models/NullableClass.ts
+++ b/samples/client/petstore/typescript-fetch/builds/default-v3.0/models/NullableClass.ts
@@ -82,16 +82,16 @@ export interface NullableClass {
     objectNullableProp?: { [key: string]: object; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    objectAndItemsNullableProp?: { [key: string]: object; } | null;
+    objectAndItemsNullableProp?: { [key: string]: object | null; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    objectItemsNullable?: { [key: string]: object; };
+    objectItemsNullable?: { [key: string]: object | null; };
 }
 
 /**
diff --git a/samples/client/petstore/typescript-fetch/builds/snakecase-discriminator/models/NullableClass.ts b/samples/client/petstore/typescript-fetch/builds/snakecase-discriminator/models/NullableClass.ts
index 94b8e43e6f5..52e1a217164 100644
--- a/samples/client/petstore/typescript-fetch/builds/snakecase-discriminator/models/NullableClass.ts
+++ b/samples/client/petstore/typescript-fetch/builds/snakecase-discriminator/models/NullableClass.ts
@@ -82,16 +82,16 @@ export interface NullableClass {
     objectNullableProp?: { [key: string]: object; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    objectAndItemsNullableProp?: { [key: string]: object; } | null;
+    objectAndItemsNullableProp?: { [key: string]: object | null; } | null;
     /**
      * 
-     * @type {{ [key: string]: object; }}
+     * @type {{ [key: string]: object | null; }}
      * @memberof NullableClass
      */
-    objectItemsNullable?: { [key: string]: object; };
+    objectItemsNullable?: { [key: string]: object | null; };
 }
 
 /**