diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
index 38b3f71ac6c..85ac755a42c 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
@@ -236,9 +236,23 @@ public class TypeScriptFetchClientCodegen extends AbstractTypeScriptClientCodege
         this.addOperationObjectResponseInformation(operations);
         this.addOperationPrefixParameterInterfacesInformation(operations);
         this.escapeOperationIds(operations);
+        this.addDeepObjectVendorExtension(operations);
         return operations;
     }
 
+    private void addDeepObjectVendorExtension(Map<String, Object> operations) {
+        Map<String, Object> _operations = (Map<String, Object>) operations.get("operations");
+        List<CodegenOperation> operationList = (List<CodegenOperation>) _operations.get("operation");
+
+        for (CodegenOperation op : operationList) {
+            for (CodegenParameter param : op.queryParams) {
+                if (param.style != null && param.style.equals("deepObject")) {
+                    param.vendorExtensions.put("x-codegen-isDeepObject", true);
+                }
+            }
+        }
+    }
+
     private void escapeOperationIds(Map<String, Object> operations) {
         Map<String, Object> _operations = (Map<String, Object>) operations.get("operations");
         List<CodegenOperation> operationList = (List<CodegenOperation>) _operations.get("operation");
diff --git a/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache b/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
index ace07d5b962..39ed958da28 100644
--- a/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache
@@ -122,7 +122,12 @@ export class {{classname}} extends runtime.BaseAPI {
             queryParameters['{{baseName}}'] = (requestParameters.{{paramName}} as any).toISOString().substr(0,10);
             {{/isDate}}
             {{^isDate}}
+            {{#vendorExtensions.x-codegen-isDeepObject}}
+            queryParameters['{{baseName}}'] = runtime.querystring(requestParameters.{{paramName}} as unknown as runtime.HTTPQuery, '{{baseName}}');
+            {{/vendorExtensions.x-codegen-isDeepObject}}
+            {{^vendorExtensions.x-codegen-isDeepObject}}
             queryParameters['{{baseName}}'] = requestParameters.{{paramName}};
+            {{/vendorExtensions.x-codegen-isDeepObject}}
             {{/isDate}}
             {{/isDateTime}}
         }