diff --git a/mmv1/products/alloydb/Cluster.yaml b/mmv1/products/alloydb/Cluster.yaml
index ad5967241524..bc3ac954e488 100644
--- a/mmv1/products/alloydb/Cluster.yaml
+++ b/mmv1/products/alloydb/Cluster.yaml
@@ -262,7 +262,8 @@ properties:
   - name: 'databaseVersion'
     type: String
     description: |
-      The database engine major version. This is an optional field and it's populated at the Cluster creation time. This field cannot be changed after cluster creation.
+      The database engine major version. This is an optional field and it's populated at the Cluster creation time.
+      Note: Changing this field to a higer version results in upgrading the AlloyDB cluster which is an irreversible change.
     default_from_api: true
   - name: 'pscConfig'
     type: NestedObject
diff --git a/mmv1/templates/terraform/pre_update/alloydb_cluster.go.tmpl b/mmv1/templates/terraform/pre_update/alloydb_cluster.go.tmpl
index dcbd075fb019..1829997b0644 100644
--- a/mmv1/templates/terraform/pre_update/alloydb_cluster.go.tmpl
+++ b/mmv1/templates/terraform/pre_update/alloydb_cluster.go.tmpl
@@ -1,3 +1,37 @@
+// Implementation for cluster upgrade
+if d.HasChange("database_version") && !tpgresource.IsEmptyValue(reflect.ValueOf(d.Get("database_version"))) {
+    upgradeUrl := strings.Split(url, "?updateMask")[0] + ":upgrade"
+    patchObj := make(map[string]interface{})
+    patchObj["version"] = obj["databaseVersion"]
+    if bp, err := tpgresource.GetBillingProject(d, config); err == nil {
+        billingProject = bp
+    }
+
+    upgradeClusterTimeout := 58 * time.Hour
+    res, err := transport_tpg.SendRequest(transport_tpg.SendRequestOptions{
+        Config: config,
+        Method: "PATCH",
+        Project: billingProject,
+        RawURL: upgradeUrl,
+        UserAgent: userAgent,
+        Body: patchObj,
+        Timeout: upgradeClusterTimeout,
+    })
+    if err != nil {
+        return fmt.Errorf("Error upgrading cluster: %v", err)
+    }
+
+    err = AlloydbOperationWaitTime(
+        config, res, project, "Upgrading cluster", userAgent,
+        upgradeClusterTimeout)
+
+    if err != nil {
+        return fmt.Errorf("Error waiting to upgrade cluster: %s", err)
+    }
+
+    log.Printf("[DEBUG] Finished upgrading cluster %q: %#v", d.Id(), res)
+}
+
 // Restrict setting secondary_config if cluster_type is PRIMARY
 if d.Get("cluster_type") == "PRIMARY" && !tpgresource.IsEmptyValue(reflect.ValueOf(d.Get("secondary_config"))) {
     return fmt.Errorf("Can not set secondary config for primary cluster.")
diff --git a/mmv1/third_party/terraform/services/alloydb/resource_alloydb_cluster_test.go b/mmv1/third_party/terraform/services/alloydb/resource_alloydb_cluster_test.go
index 5982f83a2f4b..7f305e3be9e0 100644
--- a/mmv1/third_party/terraform/services/alloydb/resource_alloydb_cluster_test.go
+++ b/mmv1/third_party/terraform/services/alloydb/resource_alloydb_cluster_test.go
@@ -56,21 +56,106 @@ resource "google_alloydb_cluster" "default" {
   network_config {
     network = "projects/${data.google_project.project.number}/global/networks/${google_compute_network.default.name}"
   }
+}
+
+data "google_project" "project" {
+}
+
+resource "google_compute_network" "default" {
+  name = "tf-test-alloydb-cluster%{random_suffix}"
+}
+`, context)
+}
+
+func TestAccAlloydbCluster_upgrade(t *testing.T) {
+	t.Parallel()
+
+	context := map[string]interface{}{
+		"network_name":  acctest.BootstrapSharedServiceNetworkingConnection(t, "alloydb-instance-upgrade-1"),
+		"random_suffix": acctest.RandString(t, 10),
+	}
+
+	acctest.VcrTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.AccTestPreCheck(t) },
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories(t),
+		CheckDestroy:             testAccCheckAlloydbClusterDestroyProducer(t),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAlloydbCluster_beforeUpgrade(context),
+			},
+			{
+				ResourceName:            "google_alloydb_cluster.default",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"initial_user", "cluster_id", "location", "labels", "terraform_labels"},
+			},
+			{
+				Config: testAccAlloydbCluster_afterUpgrade(context),
+			},
+			{
+				ResourceName:            "google_alloydb_cluster.default",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"initial_user", "cluster_id", "location", "labels", "terraform_labels"},
+			},
+		},
+	})
+}
+
+func testAccAlloydbCluster_beforeUpgrade(context map[string]interface{}) string {
+	return acctest.Nprintf(`
+resource "google_alloydb_cluster" "default" {
+  cluster_id = "tf-test-alloydb-cluster%{random_suffix}"
+  location   = "us-central1"
+  network_config {
+    network = data.google_compute_network.default.id
+  }
 
   labels = {
-	foo = "bar" 
+	test = "tf-test-alloydb-cluster%{random_suffix}"
   }
+  database_version = "POSTGRES_14"
+}
 
-  lifecycle {
-    prevent_destroy = true
+resource "google_alloydb_instance" "default" {
+  cluster       = google_alloydb_cluster.default.name
+  instance_id   = "tf-test-alloydb-instance%{random_suffix}"
+  instance_type = "PRIMARY"
+
+  machine_config {
+    cpu_count = 8
   }
 }
 
-data "google_project" "project" {
+data "google_compute_network" "default" {
+  name = "%{network_name}"
+}
+`, context)
 }
 
-resource "google_compute_network" "default" {
-  name = "tf-test-alloydb-cluster%{random_suffix}"
+func testAccAlloydbCluster_afterUpgrade(context map[string]interface{}) string {
+	return acctest.Nprintf(`
+resource "google_alloydb_cluster" "default" {
+  cluster_id = "tf-test-alloydb-cluster%{random_suffix}"
+  location   = "us-central1"
+  network_config {
+    network = data.google_compute_network.default.id
+  }
+  database_version = "POSTGRES_15"
+}
+
+resource "google_alloydb_instance" "default" {
+  cluster       = google_alloydb_cluster.default.name
+  instance_id   = "tf-test-alloydb-instance%{random_suffix}"
+  instance_type = "PRIMARY"
+
+  machine_config {
+    cpu_count = 4
+  }
+}
+
+data "google_compute_network" "default" {
+  name = "%{network_name}"
 }
 `, context)
 }