diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
index 3969c08d391..0b74114ac5e 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
@@ -102,6 +102,23 @@ public class ApiClient {
         authentications = Collections.unmodifiableMap(authentications);
     }
 
+    /*
+     * Basic constructor with custom OkHttpClient
+     */
+    public ApiClient(OkHttpClient client) {
+        init();
+
+        httpClient = client;
+
+        // Setup authentications (key: authentication name, value: authentication).{{#authMethods}}{{#isBasic}}{{#isBasicBasic}}
+        authentications.put("{{name}}", new HttpBasicAuth());{{/isBasicBasic}}{{^isBasicBasic}}
+        authentications.put("{{name}}", new HttpBearerAuth("{{scheme}}"));{{/isBasicBasic}}{{/isBasic}}{{#isApiKey}}
+        authentications.put("{{name}}", new ApiKeyAuth({{#isKeyInHeader}}"header"{{/isKeyInHeader}}{{#isKeyInQuery}}"query"{{/isKeyInQuery}}{{#isKeyInCookie}}"cookie"{{/isKeyInCookie}}, "{{keyParamName}}"));{{/isApiKey}}{{#isOAuth}}
+        authentications.put("{{name}}", new OAuth());{{/isOAuth}}{{/authMethods}}
+        // Prevent the authentications from being modified.
+        authentications = Collections.unmodifiableMap(authentications);
+    }
+
     {{#hasOAuthMethods}}
     {{#oauthMethods}}
     {{#-first}}
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
index b4072319ad5..bc4e2bdbe0a 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
@@ -97,6 +97,23 @@ public class ApiClient {
         authentications = Collections.unmodifiableMap(authentications);
     }
 
+    /*
+     * Basic constructor with custom OkHttpClient
+     */
+    public ApiClient(OkHttpClient client) {
+        init();
+
+        httpClient = client;
+
+        // Setup authentications (key: authentication name, value: authentication).
+        authentications.put("api_key", new ApiKeyAuth("header", "api_key"));
+        authentications.put("api_key_query", new ApiKeyAuth("query", "api_key_query"));
+        authentications.put("http_basic_test", new HttpBasicAuth());
+        authentications.put("petstore_auth", new OAuth());
+        // Prevent the authentications from being modified.
+        authentications = Collections.unmodifiableMap(authentications);
+    }
+
     /*
      * Constructor for ApiClient to support access token retry on 401/403 configured with client ID
      */
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
index b4072319ad5..bc4e2bdbe0a 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
@@ -97,6 +97,23 @@ public class ApiClient {
         authentications = Collections.unmodifiableMap(authentications);
     }
 
+    /*
+     * Basic constructor with custom OkHttpClient
+     */
+    public ApiClient(OkHttpClient client) {
+        init();
+
+        httpClient = client;
+
+        // Setup authentications (key: authentication name, value: authentication).
+        authentications.put("api_key", new ApiKeyAuth("header", "api_key"));
+        authentications.put("api_key_query", new ApiKeyAuth("query", "api_key_query"));
+        authentications.put("http_basic_test", new HttpBasicAuth());
+        authentications.put("petstore_auth", new OAuth());
+        // Prevent the authentications from being modified.
+        authentications = Collections.unmodifiableMap(authentications);
+    }
+
     /*
      * Constructor for ApiClient to support access token retry on 401/403 configured with client ID
      */