diff --git a/specification/network/resource-manager/Microsoft.Network/stable/2019-11-01/applicationGateway.json b/specification/network/resource-manager/Microsoft.Network/stable/2019-11-01/applicationGateway.json
index 6f11d92755cd..ee5347ac08ea 100644
--- a/specification/network/resource-manager/Microsoft.Network/stable/2019-11-01/applicationGateway.json
+++ b/specification/network/resource-manager/Microsoft.Network/stable/2019-11-01/applicationGateway.json
@@ -1569,7 +1569,7 @@
           "$ref": "./network.json#/definitions/SubResource",
           "description": "Reference to the FirewallPolicy resource."
         },
-        "hostnames": {
+        "hostNames": {
           "type": "array",
           "items": {
             "type": "string"