diff --git a/packages/@aws-cdk/aws-apigatewayv2/lib/http/api-mapping.ts b/packages/@aws-cdk/aws-apigatewayv2/lib/http/api-mapping.ts
index 550418e71bfa2..855c6a1f30638 100644
--- a/packages/@aws-cdk/aws-apigatewayv2/lib/http/api-mapping.ts
+++ b/packages/@aws-cdk/aws-apigatewayv2/lib/http/api-mapping.ts
@@ -68,8 +68,7 @@ export class HttpApiMapping extends Resource implements IApiMapping {
       apiId: props.api.httpApiId,
       domainName: props.domainName.domainName,
       stage: props.stage?.stageName ?? '$default',
-      // if apiMappingKey is '/' we set it as undefined which maps to the root path of the domain
-      apiMappingKey: props.apiMappingKey === '/' ? undefined : props.apiMappingKey,
+      apiMappingKey: props.apiMappingKey,
     };
 
     const resource = new CfnApiMapping(this, 'Resource', apiMappingProps);
diff --git a/packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.expected.json b/packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.expected.json
similarity index 99%
rename from packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.expected.json
rename to packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.expected.json
index 65aace098df5e..2fb796e79265c 100644
--- a/packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.expected.json
+++ b/packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.expected.json
@@ -189,6 +189,7 @@
         "ApiId": {
           "Ref": "HttpProxyProdApi368B6161"
         },
+        "ApiMappingKey": "/",
         "DomainName": "apigv2.demo.com",
         "Stage": "$default"
       }
diff --git a/packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.ts b/packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.ts
similarity index 99%
rename from packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.ts
rename to packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.ts
index b371874088941..4064a256d961f 100644
--- a/packages/@aws-cdk/aws-apigatewayv2/test/http/integrations/integ.custom-domain.ts
+++ b/packages/@aws-cdk/aws-apigatewayv2/test/http/integ.custom-domain.ts
@@ -1,7 +1,7 @@
 import * as acm from '@aws-cdk/aws-certificatemanager';
 import * as lambda from '@aws-cdk/aws-lambda';
 import { App, CfnOutput, Stack } from '@aws-cdk/core';
-import { DomainName, HttpApi, LambdaProxyIntegration } from '../../../lib';
+import { DomainName, HttpApi, LambdaProxyIntegration } from '../../lib';
 
 const app = new App();