diff --git a/azurerm/resource_arm_servicebus_namespace.go b/azurerm/resource_arm_servicebus_namespace.go
index 1448412bf25e..2d243d34c0b1 100644
--- a/azurerm/resource_arm_servicebus_namespace.go
+++ b/azurerm/resource_arm_servicebus_namespace.go
@@ -77,7 +77,7 @@ func resourceArmServiceBusNamespace() *schema.Resource {
 				Type:         schema.TypeInt,
 				Optional:     true,
 				Default:      0,
-				ValidateFunc: validate.IntInSlice([]int{0, 1, 2, 4}),
+				ValidateFunc: validate.IntInSlice([]int{0, 1, 2, 4, 8}),
 			},
 
 			"default_primary_connection_string": {
@@ -155,7 +155,7 @@ func resourceArmServiceBusNamespaceCreateUpdate(d *schema.ResourceData, meta int
 			return fmt.Errorf("Service Bus SKU %q only supports `capacity` of 0", sku)
 		}
 		if strings.EqualFold(sku, string(servicebus.Premium)) && capacity.(int) == 0 {
-			return fmt.Errorf("Service Bus SKU %q only supports `capacity` of 1, 2 or 4", sku)
+			return fmt.Errorf("Service Bus SKU %q only supports `capacity` of 1, 2, 4 or 8", sku)
 		}
 		parameters.Sku.Capacity = utils.Int32(int32(capacity.(int)))
 	}
diff --git a/azurerm/resource_arm_servicebus_namespace_test.go b/azurerm/resource_arm_servicebus_namespace_test.go
index 8585caa5e4e7..3e50f99335f5 100644
--- a/azurerm/resource_arm_servicebus_namespace_test.go
+++ b/azurerm/resource_arm_servicebus_namespace_test.go
@@ -175,7 +175,7 @@ func TestAccAzureRMServiceBusNamespace_premiumCapacity(t *testing.T) {
 		Steps: []resource.TestStep{
 			{
 				Config:      config,
-				ExpectError: regexp.MustCompile("Service Bus SKU \"Premium\" only supports `capacity` of 1, 2 or 4"),
+				ExpectError: regexp.MustCompile("Service Bus SKU \"Premium\" only supports `capacity` of 1, 2, 4 or 8"),
 			},
 		},
 	})
diff --git a/website/docs/r/servicebus_namespace.html.markdown b/website/docs/r/servicebus_namespace.html.markdown
index 3f52f6f4e986..87d88ea38cde 100644
--- a/website/docs/r/servicebus_namespace.html.markdown
+++ b/website/docs/r/servicebus_namespace.html.markdown
@@ -44,7 +44,7 @@ The following arguments are supported:
 
 * `sku` - (Required) Defines which tier to use. Options are basic, standard or premium.
 
-* `capacity` - (Optional) Specifies the capacity. When `sku` is `Premium` can be `1`, `2` or `4`. When `sku` is `Basic` or `Standard` can be `0` only.
+* `capacity` - (Optional) Specifies the capacity. When `sku` is `Premium`, capacity can be `1`, `2`, `4` or `8`. When `sku` is `Basic` or `Standard`, capacity can be `0` only.
 
 * `zone_redundant` - (Optional) Whether or not this resource is zone redundant. `sku` needs to be `Premium`. Defaults to `false`.