diff --git a/saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactory.java b/saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactory.java
index 2755a288dd..035a2dec4c 100644
--- a/saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactory.java
+++ b/saml2/saml2-service-provider/src/main/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactory.java
@@ -16,6 +16,7 @@
 
 package org.springframework.security.saml2.provider.service.authentication;
 
+import org.opensaml.saml.common.xml.SAMLConstants;
 import org.springframework.util.Assert;
 
 import org.joda.time.DateTime;
@@ -32,6 +33,7 @@ import java.util.UUID;
 public class OpenSamlAuthenticationRequestFactory implements Saml2AuthenticationRequestFactory {
 	private Clock clock = Clock.systemUTC();
 	private final OpenSamlImplementation saml = OpenSamlImplementation.getInstance();
+	private String protocolBinding = SAMLConstants.SAML2_POST_BINDING_URI;
 
 	/**
 	 * {@inheritDoc}
@@ -43,7 +45,7 @@ public class OpenSamlAuthenticationRequestFactory implements Saml2Authentication
 		auth.setIssueInstant(new DateTime(this.clock.millis()));
 		auth.setForceAuthn(Boolean.FALSE);
 		auth.setIsPassive(Boolean.FALSE);
-		auth.setProtocolBinding("urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect");
+		auth.setProtocolBinding(protocolBinding);
 		Issuer issuer = this.saml.buildSAMLObject(Issuer.class);
 		issuer.setValue(request.getIssuer());
 		auth.setIssuer(issuer);
@@ -67,4 +69,21 @@ public class OpenSamlAuthenticationRequestFactory implements Saml2Authentication
 		Assert.notNull(clock, "clock cannot be null");
 		this.clock = clock;
 	}
+
+	/**
+	 * Sets the {@code protocolBinding} to use when generating authentication requests
+	 * Acceptable values are {@link SAMLConstants#SAML2_POST_BINDING_URI} and
+	 * {@link SAMLConstants#SAML2_REDIRECT_BINDING_URI}
+	 *
+	 * @param protocolBinding
+	 * @throws IllegalArgumentException if the protocolBinding is not valid
+	 */
+	public void setProtocolBinding(String protocolBinding) {
+		boolean isAllowedBinding = SAMLConstants.SAML2_POST_BINDING_URI.equals(protocolBinding) ||
+				SAMLConstants.SAML2_REDIRECT_BINDING_URI.equals(protocolBinding);
+		if (!isAllowedBinding) {
+			throw new IllegalArgumentException("Invalid protocol binding: " + protocolBinding);
+		}
+		this.protocolBinding = protocolBinding;
+	}
 }
diff --git a/saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactoryTests.java b/saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactoryTests.java
new file mode 100644
index 0000000000..b7823e07c5
--- /dev/null
+++ b/saml2/saml2-service-provider/src/test/java/org/springframework/security/saml2/provider/service/authentication/OpenSamlAuthenticationRequestFactoryTests.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.security.saml2.provider.service.authentication;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.opensaml.saml.common.xml.SAMLConstants;
+import org.opensaml.saml.saml2.core.AuthnRequest;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.springframework.security.saml2.provider.service.authentication.TestSaml2X509Credentials.relyingPartyCredentials;
+
+public class OpenSamlAuthenticationRequestFactoryTests {
+
+	private OpenSamlAuthenticationRequestFactory factory;
+	private Saml2AuthenticationRequest request;
+
+	@Rule
+	public ExpectedException exception = ExpectedException.none();
+
+	@Before
+	public void setUp() {
+		request = Saml2AuthenticationRequest.builder()
+				.issuer("https://issuer")
+				.destination("https://destination/sso")
+				.assertionConsumerServiceUrl("https://issuer/sso")
+				.credentials(c -> c.addAll(relyingPartyCredentials()))
+				.build();
+		factory = new OpenSamlAuthenticationRequestFactory();
+	}
+
+	@Test
+	public void createAuthenticationRequestWhenDefaultThenReturnsPostBinding() {
+		AuthnRequest authn = getAuthNRequest();
+		Assert.assertEquals(SAMLConstants.SAML2_POST_BINDING_URI, authn.getProtocolBinding());
+	}
+
+	@Test
+	public void createAuthenticationRequestWhenSetUriThenReturnsCorrectBinding() {
+		factory.setProtocolBinding(SAMLConstants.SAML2_REDIRECT_BINDING_URI);
+		AuthnRequest authn = getAuthNRequest();
+		Assert.assertEquals(SAMLConstants.SAML2_REDIRECT_BINDING_URI, authn.getProtocolBinding());
+	}
+
+	@Test
+	public void createAuthenticationRequestWhenSetUnsupportredUriThenThrowsIllegalArgumentException() {
+		exception.expect(IllegalArgumentException.class);
+		exception.expectMessage(containsString("my-invalid-binding"));
+		factory.setProtocolBinding("my-invalid-binding");
+	}
+
+	private AuthnRequest getAuthNRequest() {
+		String xml = factory.createAuthenticationRequest(request);
+		return (AuthnRequest) OpenSamlImplementation.getInstance().resolve(xml);
+	}
+}