diff --git a/packages/aws-cdk-lib/aws-rds/lib/aurora-cluster-instance.ts b/packages/aws-cdk-lib/aws-rds/lib/aurora-cluster-instance.ts
index 359bd3f159c2e..19ad18f4af748 100644
--- a/packages/aws-cdk-lib/aws-rds/lib/aurora-cluster-instance.ts
+++ b/packages/aws-cdk-lib/aws-rds/lib/aurora-cluster-instance.ts
@@ -518,7 +518,7 @@ class AuroraClusterInstance extends Resource implements IAuroraClusterInstance {
     // Enhanced CDK Analytics Telemetry
     addConstructMetadata(this, props);
     this.tier = props.promotionTier ?? 2;
-    if (this.tier > 15) {
+    if (this.tier < 0 || this.tier > 15) {
       throw new ValidationError(lit`PromotionTier`, 'promotionTier must be between 0-15', this);
     }
 
diff --git a/packages/aws-cdk-lib/aws-rds/test/cluster.test.ts b/packages/aws-cdk-lib/aws-rds/test/cluster.test.ts
index 0188fde277936..63456636121f6 100644
--- a/packages/aws-cdk-lib/aws-rds/test/cluster.test.ts
+++ b/packages/aws-cdk-lib/aws-rds/test/cluster.test.ts
@@ -140,6 +140,29 @@ describe('cluster new api', () => {
       }).toThrow(/Provide either vpcSubnets or instanceProps.vpcSubnets, but not both/);
     });
 
+    test.each([
+      -1, 16,
+    ])('when promotionTier is %s', (promotionTier) => {
+      // GIVEN
+      const stack = testStack();
+      const vpc = new ec2.Vpc(stack, 'VPC');
+
+      expect(() => {
+        // WHEN
+        new DatabaseCluster(stack, 'Database', {
+          engine: DatabaseClusterEngine.AURORA_MYSQL,
+          vpc,
+          writer: ClusterInstance.provisioned('writer'),
+          readers: [
+            ClusterInstance.provisioned('reader', {
+              promotionTier,
+            }),
+          ],
+        });
+        // THEN
+      }).toThrow(/promotionTier must be between 0-15/);
+    });
+
     test.each([
       [0.5, 300, /serverlessV2MaxCapacity must be >= 1 & <= 256/],
       [0.5, 0, /serverlessV2MaxCapacity must be >= 1 & <= 256/],