diff --git a/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/ToOneOnDeleteTest.java b/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/ToOneOnDeleteTest.java
index 330af2637afa..f7b603dd9525 100644
--- a/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/ToOneOnDeleteTest.java
+++ b/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/ToOneOnDeleteTest.java
@@ -8,7 +8,9 @@
 import org.hibernate.Session;
 import org.hibernate.annotations.OnDelete;
 import org.hibernate.annotations.OnDeleteAction;
+import org.hibernate.dialect.SybaseDialect;
 
+import org.hibernate.testing.SkipForDialect;
 import org.hibernate.testing.junit4.BaseNonConfigCoreFunctionalTestCase;
 import org.junit.Test;
 
@@ -18,6 +20,11 @@
 public class ToOneOnDeleteTest extends BaseNonConfigCoreFunctionalTestCase {
 
 	@Test
+	@SkipForDialect(
+			value = SybaseDialect.class,
+			jiraKey = "HHH-13559",
+			comment = "on-delete=\"cascade\" is not supported for unidirectional to-one associations using Sybase"
+	)
 	public void testManyToOne() throws Exception {
 		Session session = openSession();
 		session.getTransaction().begin();
diff --git a/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/hbm/ToOneOnDeleteHbmTest.java b/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/hbm/ToOneOnDeleteHbmTest.java
index b887e6a40746..7ac3f1d5dbdc 100644
--- a/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/hbm/ToOneOnDeleteHbmTest.java
+++ b/hibernate-core/src/test/java/org/hibernate/test/ondelete/toone/hbm/ToOneOnDeleteHbmTest.java
@@ -7,7 +7,9 @@
 package org.hibernate.test.ondelete.toone.hbm;
 
 import org.hibernate.Session;
+import org.hibernate.dialect.SybaseDialect;
 
+import org.hibernate.testing.SkipForDialect;
 import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
 import org.junit.Test;
 
@@ -17,6 +19,11 @@
 public class ToOneOnDeleteHbmTest extends BaseCoreFunctionalTestCase {
 
 	@Test
+	@SkipForDialect(
+			value = SybaseDialect.class,
+			jiraKey = "HHH-13559",
+			comment = "on-delete=\"cascade\" is not supported for unidirectional to-one associations using Sybase"
+	)
 	public void testManyToOne() throws Exception {
 		Session session = openSession();
 		session.getTransaction().begin();