diff --git a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java
index a4d7c30e2c..1d0b8da8ab 100644
--- a/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java
+++ b/spring-orm/src/main/java/org/springframework/orm/hibernate5/HibernateTransactionManager.java
@@ -495,6 +495,8 @@ public class HibernateTransactionManager extends AbstractPlatformTransactionMana
 			if (definition.isReadOnly() && txObject.isNewSession()) {
 				// Just set to MANUAL in case of a new Session for this transaction.
 				session.setFlushMode(FlushMode.MANUAL);
+				// As of 5.1, we're also setting Hibernate's read-only entity mode by default.
+				session.setDefaultReadOnly(true);
 			}
 
 			if (!definition.isReadOnly() && !txObject.isNewSession()) {
diff --git a/spring-test/src/test/java/org/springframework/test/context/junit4/orm/HibernateSessionFlushingTests.java b/spring-test/src/test/java/org/springframework/test/context/junit4/orm/HibernateSessionFlushingTests.java
index f6d688f01f..fd3d5b73a2 100644
--- a/spring-test/src/test/java/org/springframework/test/context/junit4/orm/HibernateSessionFlushingTests.java
+++ b/spring-test/src/test/java/org/springframework/test/context/junit4/orm/HibernateSessionFlushingTests.java
@@ -18,6 +18,7 @@ package org.springframework.test.context.junit4.orm;
 
 import javax.persistence.PersistenceException;
 
+import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.exception.ConstraintViolationException;
 import org.junit.Before;
@@ -29,6 +30,7 @@ import org.springframework.test.context.junit4.AbstractTransactionalJUnit4Spring
 import org.springframework.test.context.junit4.orm.domain.DriversLicense;
 import org.springframework.test.context.junit4.orm.domain.Person;
 import org.springframework.test.context.junit4.orm.service.PersonService;
+import org.springframework.transaction.annotation.Transactional;
 
 import static org.junit.Assert.*;
 import static org.springframework.test.transaction.TransactionTestUtils.*;
@@ -38,6 +40,8 @@ import static org.springframework.test.transaction.TransactionTestUtils.*;
  * Hibernate.
  *
  * @author Sam Brannen
+ * @author Juergen Hoeller
+ * @author Vlad Mihalcea
  * @since 3.0
  */
 @ContextConfiguration
@@ -53,21 +57,14 @@ public class HibernateSessionFlushingTests extends AbstractTransactionalJUnit4Sp
 	private SessionFactory sessionFactory;
 
 
-	protected int countRowsInPersonTable() {
-		return countRowsInTable("person");
-	}
-
-	protected void assertPersonCount(int expectedCount) {
-		assertEquals("Verifying number of rows in the 'person' table.", expectedCount, countRowsInPersonTable());
-	}
-
 	@Before
-	public void setUp() {
+	public void setup() {
 		assertInTransaction(true);
 		assertNotNull("PersonService should have been autowired.", personService);
 		assertNotNull("SessionFactory should have been autowired.", sessionFactory);
 	}
 
+
 	@Test
 	public void findSam() {
 		Person sam = personService.findByName(SAM);
@@ -77,13 +74,25 @@ public class HibernateSessionFlushingTests extends AbstractTransactionalJUnit4Sp
 		assertEquals("Verifying Sam's driver's license number", Long.valueOf(1234), driversLicense.getNumber());
 	}
 
+	@Test  // SPR-16956
+	@Transactional(readOnly = true)
+	public void findSamWithReadOnlySession() {
+		Person sam = personService.findByName(SAM);
+		sam.setName("Vlad");
+		// By setting setDefaultReadOnly(true), the user can no longer modify any entity...
+		Session session = sessionFactory.getCurrentSession();
+		session.flush();
+		session.refresh(sam);
+		assertEquals("Sam", sam.getName());
+	}
+
 	@Test
 	public void saveJuergenWithDriversLicense() {
 		DriversLicense driversLicense = new DriversLicense(2L, 2222L);
 		Person juergen = new Person(JUERGEN, driversLicense);
-		int numRows = countRowsInPersonTable();
+		int numRows = countRowsInTable("person");
 		personService.save(juergen);
-		assertPersonCount(numRows + 1);
+		assertEquals("Verifying number of rows in the 'person' table.", numRows + 1, countRowsInTable("person"));
 		assertNotNull("Should be able to save and retrieve Juergen", personService.findByName(JUERGEN));
 		assertNotNull("Juergen's ID should have been set", juergen.getId());
 	}
@@ -93,13 +102,6 @@ public class HibernateSessionFlushingTests extends AbstractTransactionalJUnit4Sp
 		personService.save(new Person(JUERGEN));
 	}
 
-	private void updateSamWithNullDriversLicense() {
-		Person sam = personService.findByName(SAM);
-		assertNotNull("Should be able to find Sam", sam);
-		sam.setDriversLicense(null);
-		personService.save(sam);
-	}
-
 	@Test
 	// no expected exception!
 	public void updateSamWithNullDriversLicenseWithoutSessionFlush() {
@@ -121,4 +123,11 @@ public class HibernateSessionFlushingTests extends AbstractTransactionalJUnit4Sp
 		}
 	}
 
+	private void updateSamWithNullDriversLicense() {
+		Person sam = personService.findByName(SAM);
+		assertNotNull("Should be able to find Sam", sam);
+		sam.setDriversLicense(null);
+		personService.save(sam);
+	}
+
 }