diff --git a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/OAuth2AuthorizedClient.java b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/OAuth2AuthorizedClient.java
index 298658324a..052e481464 100644
--- a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/OAuth2AuthorizedClient.java
+++ b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/OAuth2AuthorizedClient.java
@@ -16,11 +16,14 @@
 package org.springframework.security.oauth2.client;
 
 import org.springframework.lang.Nullable;
+import org.springframework.security.core.SpringSecurityCoreVersion;
 import org.springframework.security.oauth2.client.registration.ClientRegistration;
 import org.springframework.security.oauth2.core.OAuth2AccessToken;
 import org.springframework.security.oauth2.core.OAuth2RefreshToken;
 import org.springframework.util.Assert;
 
+import java.io.Serializable;
+
 /**
  * A representation of an OAuth 2.0 "Authorized Client".
  * <p>
@@ -37,7 +40,8 @@ import org.springframework.util.Assert;
  * @see OAuth2AccessToken
  * @see OAuth2RefreshToken
  */
-public class OAuth2AuthorizedClient {
+public class OAuth2AuthorizedClient implements Serializable {
+	private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 	private final ClientRegistration clientRegistration;
 	private final String principalName;
 	private final OAuth2AccessToken accessToken;
diff --git a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/registration/ClientRegistration.java b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/registration/ClientRegistration.java
index 1251489c70..a011a2a5de 100644
--- a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/registration/ClientRegistration.java
+++ b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/registration/ClientRegistration.java
@@ -15,12 +15,14 @@
  */
 package org.springframework.security.oauth2.client.registration;
 
+import org.springframework.security.core.SpringSecurityCoreVersion;
 import org.springframework.security.oauth2.core.AuthenticationMethod;
 import org.springframework.security.oauth2.core.AuthorizationGrantType;
 import org.springframework.security.oauth2.core.ClientAuthenticationMethod;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
+import java.io.Serializable;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -36,7 +38,8 @@ import java.util.Set;
  * @since 5.0
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-2">Section 2 Client Registration</a>
  */
-public final class ClientRegistration {
+public final class ClientRegistration implements Serializable {
+	private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 	private String registrationId;
 	private String clientId;
 	private String clientSecret;
@@ -150,7 +153,8 @@ public final class ClientRegistration {
 	/**
 	 * Details of the Provider.
 	 */
-	public class ProviderDetails {
+	public class ProviderDetails implements Serializable {
+		private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 		private String authorizationUri;
 		private String tokenUri;
 		private UserInfoEndpoint userInfoEndpoint = new UserInfoEndpoint();
@@ -209,7 +213,8 @@ public final class ClientRegistration {
 		/**
 		 * Details of the UserInfo Endpoint.
 		 */
-		public class UserInfoEndpoint {
+		public class UserInfoEndpoint implements Serializable {
+			private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 			private String uri;
 			private AuthenticationMethod authenticationMethod = AuthenticationMethod.HEADER;
 			private String userNameAttributeName;
@@ -261,7 +266,8 @@ public final class ClientRegistration {
 	/**
 	 * A builder for {@link ClientRegistration}.
 	 */
-	public static class Builder {
+	public static class Builder implements Serializable {
+		private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 		private String registrationId;
 		private String clientId;
 		private String clientSecret;
diff --git a/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/ClientAuthenticationMethod.java b/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/ClientAuthenticationMethod.java
index 421cd2183d..551b26a839 100644
--- a/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/ClientAuthenticationMethod.java
+++ b/oauth2/oauth2-core/src/main/java/org/springframework/security/oauth2/core/ClientAuthenticationMethod.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -15,8 +15,11 @@
  */
 package org.springframework.security.oauth2.core;
 
+import org.springframework.security.core.SpringSecurityCoreVersion;
 import org.springframework.util.Assert;
 
+import java.io.Serializable;
+
 /**
  * The authentication method used when authenticating the client with the authorization server.
  *
@@ -24,7 +27,8 @@ import org.springframework.util.Assert;
  * @since 5.0
  * @see <a target="_blank" href="https://tools.ietf.org/html/rfc6749#section-2.3">Section 2.3 Client Authentication</a>
  */
-public final class ClientAuthenticationMethod {
+public final class ClientAuthenticationMethod implements Serializable {
+	private static final long serialVersionUID = SpringSecurityCoreVersion.SERIAL_VERSION_UID;
 	public static final ClientAuthenticationMethod BASIC = new ClientAuthenticationMethod("basic");
 	public static final ClientAuthenticationMethod POST = new ClientAuthenticationMethod("post");
 	private final String value;