diff --git a/builtin/providers/google/resource_compute_instance.go b/builtin/providers/google/resource_compute_instance.go
index 3b3e86ded..572d77310 100644
--- a/builtin/providers/google/resource_compute_instance.go
+++ b/builtin/providers/google/resource_compute_instance.go
@@ -74,6 +74,12 @@ func resourceComputeInstance() *schema.Resource {
 							Optional: true,
 							ForceNew: true,
 						},
+
+						"size": &schema.Schema{
+							Type:     schema.TypeInt,
+							Optional: true,
+							ForceNew: true,
+						},
 					},
 				},
 			},
@@ -331,6 +337,11 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 			disk.InitializeParams.DiskType = diskType.SelfLink
 		}
 
+		if v, ok := d.GetOk(prefix + ".size"); ok {
+			diskSizeGb := v.(int)
+			disk.InitializeParams.DiskSizeGb = int64(diskSizeGb)
+		}
+
 		disks = append(disks, &disk)
 	}
 
diff --git a/website/source/docs/providers/google/r/compute_instance.html.markdown b/website/source/docs/providers/google/r/compute_instance.html.markdown
index 5c6cfe027..3d3104d17 100644
--- a/website/source/docs/providers/google/r/compute_instance.html.markdown
+++ b/website/source/docs/providers/google/r/compute_instance.html.markdown
@@ -93,6 +93,9 @@ The `disk` block supports:
 
 * `type` - (Optional) The GCE disk type.
 
+* `size` - (Optional) The size of the image in gigabytes. If not specified,
+    it will inherit the size of its base image.
+
 The `network_interface` block supports:
 
 * `network` - (Required) The name of the network to attach this interface to.