diff --git a/src/php/lib/Grpc/BaseStub.php b/src/php/lib/Grpc/BaseStub.php
index 7860233ca2c..09661931075 100644
--- a/src/php/lib/Grpc/BaseStub.php
+++ b/src/php/lib/Grpc/BaseStub.php
@@ -60,7 +60,7 @@ class BaseStub
         }
         if ($channel) {
             if (!is_a($channel, 'Grpc\Channel') &&
-                !is_a($channel, 'Grpc\InterceptorChannel')) {
+                !is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
                 throw new \Exception('The channel argument is not a Channel object '.
                     'or an InterceptorChannel object created by '.
                     'Interceptor::intercept($channel, Interceptor|Interceptor[] $interceptors)');
@@ -365,7 +365,7 @@ class BaseStub
      */
     private function _UnaryUnaryCallFactory($channel, $deserialize)
     {
-        if (is_a($channel, 'Grpc\InterceptorChannel')) {
+        if (is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
             return function ($method,
                              $argument,
                              array $metadata = [],
@@ -392,7 +392,7 @@ class BaseStub
      */
     private function _UnaryStreamCallFactory($channel, $deserialize)
     {
-        if (is_a($channel, 'Grpc\InterceptorChannel')) {
+        if (is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
             return function ($method,
                              $argument,
                              array $metadata = [],
@@ -419,7 +419,7 @@ class BaseStub
      */
     private function _StreamUnaryCallFactory($channel, $deserialize)
     {
-        if (is_a($channel, 'Grpc\InterceptorChannel')) {
+        if (is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
             return function ($method,
                              array $metadata = [],
                              array $options = []) use ($channel, $deserialize) {
@@ -444,7 +444,7 @@ class BaseStub
      */
     private function _StreamStreamCallFactory($channel, $deserialize)
     {
-        if (is_a($channel, 'Grpc\InterceptorChannel')) {
+        if (is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
             return function ($method,
                              array $metadata = [],
                              array $options = []) use ($channel, $deserialize) {
diff --git a/src/php/lib/Grpc/Interceptor.php b/src/php/lib/Grpc/Interceptor.php
index 9c1b5616f25..e1b97f2a849 100644
--- a/src/php/lib/Grpc/Interceptor.php
+++ b/src/php/lib/Grpc/Interceptor.php
@@ -75,10 +75,10 @@ class Interceptor
     {
         if (is_array($interceptors)) {
             for ($i = count($interceptors) - 1; $i >= 0; $i--) {
-                $channel = new InterceptorChannel($channel, $interceptors[$i]);
+                $channel = new Internal\InterceptorChannel($channel, $interceptors[$i]);
             }
         } else {
-            $channel =  new InterceptorChannel($channel, $interceptors);
+            $channel =  new Internal\InterceptorChannel($channel, $interceptors);
         }
         return $channel;
     }
diff --git a/src/php/lib/Grpc/Internal/InterceptorChannel.php b/src/php/lib/Grpc/Internal/InterceptorChannel.php
index 9ac05748f34..4677fb5aefe 100644
--- a/src/php/lib/Grpc/Internal/InterceptorChannel.php
+++ b/src/php/lib/Grpc/Internal/InterceptorChannel.php
@@ -17,7 +17,7 @@
  *
  */
 
-namespace Grpc;
+namespace Grpc\Internal;
 
 /**
  * This is a PRIVATE API and can change without notice.
@@ -35,7 +35,7 @@ class InterceptorChannel
     public function __construct($channel, $interceptor)
     {
         if (!is_a($channel, 'Grpc\Channel') &&
-            !is_a($channel, 'Grpc\InterceptorChannel')) {
+            !is_a($channel, 'Grpc\Internal\InterceptorChannel')) {
             throw new \Exception('The channel argument is not a Channel object '.
                 'or an InterceptorChannel object created by '.
                 'Interceptor::intercept($channel, Interceptor|Interceptor[] $interceptors)');