diff --git a/builtin/providers/aws/resource_aws_autoscaling_group.go b/builtin/providers/aws/resource_aws_autoscaling_group.go
index 1e815d4656ab..6f66744dbcf7 100644
--- a/builtin/providers/aws/resource_aws_autoscaling_group.go
+++ b/builtin/providers/aws/resource_aws_autoscaling_group.go
@@ -92,6 +92,7 @@ func resourceAwsAutoscalingGroup() *schema.Resource {
 			"availability_zones": &schema.Schema{
 				Type:     schema.TypeSet,
 				Optional: true,
+				Computed: true,
 				Elem:     &schema.Schema{Type: schema.TypeString},
 				Set:      schema.HashString,
 			},
@@ -237,7 +238,7 @@ func resourceAwsAutoscalingGroupRead(d *schema.ResourceData, meta interface{}) e
 		return nil
 	}
 
-	d.Set("availability_zones", g.AvailabilityZones)
+	d.Set("availability_zones", flattenStringList(g.AvailabilityZones))
 	d.Set("default_cooldown", g.DefaultCooldown)
 	d.Set("desired_capacity", g.DesiredCapacity)
 	d.Set("health_check_grace_period", g.HealthCheckGracePeriod)
@@ -300,7 +301,7 @@ func resourceAwsAutoscalingGroupUpdate(d *schema.ResourceData, meta interface{})
 
 	if d.HasChange("availability_zones") {
 		if v, ok := d.GetOk("availability_zones"); ok && v.(*schema.Set).Len() > 0 {
-			opts.AvailabilityZones = expandStringList(d.Get("availability_zones").(*schema.Set).List())
+			opts.AvailabilityZones = expandStringList(v.(*schema.Set).List())
 		}
 	}
 
diff --git a/builtin/providers/aws/resource_aws_autoscaling_group_test.go b/builtin/providers/aws/resource_aws_autoscaling_group_test.go
index 6a5f9f30cf84..d26f47275498 100644
--- a/builtin/providers/aws/resource_aws_autoscaling_group_test.go
+++ b/builtin/providers/aws/resource_aws_autoscaling_group_test.go
@@ -138,6 +138,12 @@ func TestAccAWSAutoScalingGroup_VpcUpdates(t *testing.T) {
 				Config: testAccAWSAutoScalingGroupConfigWithAZ,
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSAutoScalingGroupExists("aws_autoscaling_group.bar", &group),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "availability_zones.#", "1"),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "availability_zones.2487133097", "us-west-2a"),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "vpc_zone_identifier.#", "1"),
 				),
 			},
 
@@ -146,6 +152,14 @@ func TestAccAWSAutoScalingGroup_VpcUpdates(t *testing.T) {
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckAWSAutoScalingGroupExists("aws_autoscaling_group.bar", &group),
 					testAccCheckAWSAutoScalingGroupAttributesVPCZoneIdentifer(&group),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "availability_zones.#", "2"),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "availability_zones.2487133097", "us-west-2a"),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "availability_zones.221770259", "us-west-2b"),
+					resource.TestCheckResourceAttr(
+						"aws_autoscaling_group.bar", "vpc_zone_identifier.#", "2"),
 				),
 			},
 		},