diff --git a/internal/services/network/application_gateway_resource.go b/internal/services/network/application_gateway_resource.go
index 2f31b168469a..6f5b3c456dca 100644
--- a/internal/services/network/application_gateway_resource.go
+++ b/internal/services/network/application_gateway_resource.go
@@ -512,12 +512,9 @@ func resourceApplicationGateway() *pluginsdk.Resource {
 							Elem: &pluginsdk.Resource{
 								Schema: map[string]*pluginsdk.Schema{
 									"status_code": {
-										Type:     pluginsdk.TypeString,
-										Required: true,
-										ValidateFunc: validation.StringInSlice([]string{
-											string(applicationgateways.ApplicationGatewayCustomErrorStatusCodeHTTPStatusFourZeroThree),
-											string(applicationgateways.ApplicationGatewayCustomErrorStatusCodeHTTPStatusFiveZeroTwo),
-										}, false),
+										Type:         pluginsdk.TypeString,
+										Required:     true,
+										ValidateFunc: validation.StringInSlice(applicationgateways.PossibleValuesForApplicationGatewayCustomErrorStatusCode(), false),
 									},
 
 									"custom_error_page_url": {
@@ -1517,12 +1514,9 @@ func resourceApplicationGateway() *pluginsdk.Resource {
 				Elem: &pluginsdk.Resource{
 					Schema: map[string]*pluginsdk.Schema{
 						"status_code": {
-							Type:     pluginsdk.TypeString,
-							Required: true,
-							ValidateFunc: validation.StringInSlice([]string{
-								string(applicationgateways.ApplicationGatewayCustomErrorStatusCodeHTTPStatusFourZeroThree),
-								string(applicationgateways.ApplicationGatewayCustomErrorStatusCodeHTTPStatusFiveZeroTwo),
-							}, false),
+							Type:         pluginsdk.TypeString,
+							Required:     true,
+							ValidateFunc: validation.StringInSlice(applicationgateways.PossibleValuesForApplicationGatewayCustomErrorStatusCode(), false),
 						},
 
 						"custom_error_page_url": {
diff --git a/internal/services/network/application_gateway_resource_test.go b/internal/services/network/application_gateway_resource_test.go
index 0ee0de00fb24..5533f5a6a585 100644
--- a/internal/services/network/application_gateway_resource_test.go
+++ b/internal/services/network/application_gateway_resource_test.go
@@ -6305,10 +6305,45 @@ resource "azurerm_application_gateway" "test" {
       custom_error_page_url = "http://azure.com/error403_listener.html"
     }
 
+    custom_error_configuration {
+      status_code           = "HttpStatus404"
+      custom_error_page_url = "http://azure.com/error404_listener.html"
+    }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus405"
+      custom_error_page_url = "http://azure.com/error405_listener.html"
+    }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus408"
+      custom_error_page_url = "http://azure.com/error408_listener.html"
+    }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus400"
+      custom_error_page_url = "http://azure.com/error400_listener.html"
+    }
+
     custom_error_configuration {
       status_code           = "HttpStatus502"
       custom_error_page_url = "http://azure.com/error502_listener.html"
     }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus503"
+      custom_error_page_url = "http://azure.com/error503_listener.html"
+    }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus504"
+      custom_error_page_url = "http://azure.com/error504_listener.html"
+    }
+
+    custom_error_configuration {
+      status_code           = "HttpStatus500"
+      custom_error_page_url = "http://azure.com/error500_listener.html"
+    }
   }
 
   custom_error_configuration {
@@ -6316,11 +6351,46 @@ resource "azurerm_application_gateway" "test" {
     custom_error_page_url = "http://azure.com/error.html"
   }
 
+  custom_error_configuration {
+    status_code           = "HttpStatus404"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
+  custom_error_configuration {
+    status_code           = "HttpStatus405"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
+  custom_error_configuration {
+    status_code           = "HttpStatus408"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
+  custom_error_configuration {
+    status_code           = "HttpStatus400"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
   custom_error_configuration {
     status_code           = "HttpStatus502"
     custom_error_page_url = "http://azure.com/error.html"
   }
 
+  custom_error_configuration {
+    status_code           = "HttpStatus503"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
+  custom_error_configuration {
+    status_code           = "HttpStatus504"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
+  custom_error_configuration {
+    status_code           = "HttpStatus500"
+    custom_error_page_url = "http://azure.com/error.html"
+  }
+
   request_routing_rule {
     name                       = local.request_routing_rule_name
     rule_type                  = "Basic"
diff --git a/website/docs/r/application_gateway.html.markdown b/website/docs/r/application_gateway.html.markdown
index 4a28c064cb07..922347a0b228 100644
--- a/website/docs/r/application_gateway.html.markdown
+++ b/website/docs/r/application_gateway.html.markdown
@@ -579,7 +579,7 @@ A `exclusion` block supports the following:
 
 A `custom_error_configuration` block supports the following:
 
-* `status_code` - (Required) Status code of the application gateway customer error. Possible values are `HttpStatus403` and `HttpStatus502`
+* `status_code` - (Required) Status code of the application gateway customer error. Possible values are `HttpStatus400`, `HttpStatus403`, `HttpStatus404`, `HttpStatus405`, `HttpStatus408`, `HttpStatus500`, `HttpStatus502`, `HttpStatus503` and `HttpStatus504`
 
 * `custom_error_page_url` - (Required) Error page URL of the application gateway customer error.