diff --git a/types/aws-lambda/aws-lambda-tests.ts b/types/aws-lambda/aws-lambda-tests.ts
index 7ceeffe04d9b0c..82a4fa90a953fc 100644
--- a/types/aws-lambda/aws-lambda-tests.ts
+++ b/types/aws-lambda/aws-lambda-tests.ts
@@ -48,7 +48,7 @@ str = identity.cognitoIdentityPoolId;
 
 /* ClientContext */
 clientContextClient = clientCtx.client;
-anyObj = clientCtx.Custom;
+anyObj = clientCtx.custom;
 clientContextEnv = clientCtx.env;
 
 /* ClientContextEnv */
diff --git a/types/aws-lambda/handler.d.ts b/types/aws-lambda/handler.d.ts
index 43847e2034d74b..3c028af040d9ac 100644
--- a/types/aws-lambda/handler.d.ts
+++ b/types/aws-lambda/handler.d.ts
@@ -131,7 +131,7 @@ export interface CognitoIdentity {
 
 export interface ClientContext {
     client: ClientContextClient;
-    Custom?: any;
+    custom?: any;
     env: ClientContextEnv;
 }