diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d36285c..e2fe02fb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Changed
+- Refactoring: extracted `validateRedirectUri` method to remove 3 code duplicates (PR #912)
+
 ### Added
 - Function `hasRedirect()` added to `OAuthServerException` (PR #703)
 
diff --git a/src/Grant/AbstractGrant.php b/src/Grant/AbstractGrant.php
index 79a1ac47..99f1626a 100644
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -193,27 +193,43 @@ abstract class AbstractGrant implements GrantTypeInterface
             throw OAuthServerException::invalidClient();
         }
 
-        // If a redirect URI is provided ensure it matches what is pre-registered
         $redirectUri = $this->getRequestParameter('redirect_uri', $request, null);
+
         if ($redirectUri !== null) {
-            if (
-                is_string($client->getRedirectUri())
-                && (strcmp($client->getRedirectUri(), $redirectUri) !== 0)
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            } elseif (
-                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri(), true) === false
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            }
+            $this->validateRedirectUri($redirectUri, $client, $request);
         }
 
         return $client;
     }
 
+    /**
+     * Validate redirectUri from the request.
+     * If a redirect URI is provided ensure it matches what is pre-registered
+     *
+     * @param string                 $redirectUri
+     * @param ClientEntityInterface  $client
+     * @param ServerRequestInterface $request
+     *
+     * @throws OAuthServerException
+     */
+    protected function validateRedirectUri(
+        string $redirectUri,
+        ClientEntityInterface $client,
+        ServerRequestInterface $request
+    ) {
+        if (is_string($client->getRedirectUri())
+            && (strcmp($client->getRedirectUri(), $redirectUri) !== 0)
+        ) {
+            $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
+            throw OAuthServerException::invalidClient();
+        } elseif (is_array($client->getRedirectUri())
+            && in_array($redirectUri, $client->getRedirectUri(), true) === false
+        ) {
+            $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
+            throw OAuthServerException::invalidClient();
+        }
+    }
+
     /**
      * Validate scopes in the request.
      *
diff --git a/src/Grant/AuthCodeGrant.php b/src/Grant/AuthCodeGrant.php
index 80e1cd0f..cfa8309b 100644
--- a/src/Grant/AuthCodeGrant.php
+++ b/src/Grant/AuthCodeGrant.php
@@ -242,19 +242,7 @@ class AuthCodeGrant extends AbstractAuthorizeGrant
         $redirectUri = $this->getQueryStringParameter('redirect_uri', $request);
 
         if ($redirectUri !== null) {
-            if (
-                is_string($client->getRedirectUri())
-                && (strcmp($client->getRedirectUri(), $redirectUri) !== 0)
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            } elseif (
-                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri(), true) === false
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            }
+            $this->validateRedirectUri($redirectUri, $client, $request);
         } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
             || empty($client->getRedirectUri())) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
diff --git a/src/Grant/ImplicitGrant.php b/src/Grant/ImplicitGrant.php
index b4157883..9810c30a 100644
--- a/src/Grant/ImplicitGrant.php
+++ b/src/Grant/ImplicitGrant.php
@@ -118,6 +118,7 @@ class ImplicitGrant extends AbstractAuthorizeGrant
             $request,
             $this->getServerParameter('PHP_AUTH_USER', $request)
         );
+
         if (is_null($clientId)) {
             throw OAuthServerException::invalidRequest('client_id');
         }
@@ -135,20 +136,9 @@ class ImplicitGrant extends AbstractAuthorizeGrant
         }
 
         $redirectUri = $this->getQueryStringParameter('redirect_uri', $request);
+
         if ($redirectUri !== null) {
-            if (
-                is_string($client->getRedirectUri())
-                && (strcmp($client->getRedirectUri(), $redirectUri) !== 0)
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            } elseif (
-                is_array($client->getRedirectUri())
-                && in_array($redirectUri, $client->getRedirectUri(), true) === false
-            ) {
-                $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));
-                throw OAuthServerException::invalidClient();
-            }
+            $this->validateRedirectUri($redirectUri, $client, $request);
         } elseif (is_array($client->getRedirectUri()) && count($client->getRedirectUri()) !== 1
             || empty($client->getRedirectUri())) {
             $this->getEmitter()->emit(new RequestEvent(RequestEvent::CLIENT_AUTHENTICATION_FAILED, $request));