diff --git a/specification/network/resource-manager/Microsoft.Network/stable/2018-12-01/applicationGateway.json b/specification/network/resource-manager/Microsoft.Network/stable/2018-12-01/applicationGateway.json
index 72846d1e1bbc..dd5e5ba1015d 100644
--- a/specification/network/resource-manager/Microsoft.Network/stable/2018-12-01/applicationGateway.json
+++ b/specification/network/resource-manager/Microsoft.Network/stable/2018-12-01/applicationGateway.json
@@ -2105,6 +2105,13 @@
           "minimum": 2,
           "exclusiveMinimum": false,
           "description": "Lower bound on number of Application Gateway instances"
+        },
+        "maxCapacity": {
+          "type": "integer",
+          "format": "int32",
+          "minimum": 2,
+          "exclusiveMinimum": false,
+          "description": "Upper bound on number of Application Gateway capacity"
         }
       },
       "required": [