diff --git a/.changes/nextrelease/changelog_endpoint_path.json b/.changes/nextrelease/changelog_endpoint_path.json
new file mode 100644
index 0000000000..1f8c71b9e4
--- /dev/null
+++ b/.changes/nextrelease/changelog_endpoint_path.json
@@ -0,0 +1,7 @@
+[
+    {
+        "type": "bugfix",
+        "category": "Api",
+        "description": "Preserve path on custom endpoints"
+    }
+]
diff --git a/src/Api/Serializer/RestSerializer.php b/src/Api/Serializer/RestSerializer.php
index 3dbb26673c..96e66cd8b1 100644
--- a/src/Api/Serializer/RestSerializer.php
+++ b/src/Api/Serializer/RestSerializer.php
@@ -212,6 +212,12 @@ function (array $matches) use ($varspecs) {
             $relative .= strpos($relative, '?') ? "&{$append}" : "?$append";
         }
 
+        // If endpoint has path, remove leading '/' to preserve URI resolution.
+        $path = $this->endpoint->getPath();
+        if ($path && $relative[0] === '/') {
+            $relative = substr($relative, 1);
+        }
+
         // Expand path place holders using Amazon's slightly different URI
         // template syntax.
         return UriResolver::resolve($this->endpoint, new Uri($relative));
diff --git a/tests/Api/Serializer/RestJsonSerializerTest.php b/tests/Api/Serializer/RestJsonSerializerTest.php
index 49b5dd669e..a118af2107 100644
--- a/tests/Api/Serializer/RestJsonSerializerTest.php
+++ b/tests/Api/Serializer/RestJsonSerializerTest.php
@@ -86,6 +86,14 @@ private function getRequest($commandName, $input)
         return $j($command);
     }
 
+    private function getPathEndpointRequest($commandName, $input)
+    {
+        $service = $this->getTestService();
+        $command = new Command($commandName, $input);
+        $j = new RestJsonSerializer($service, 'http://foo.com/bar');
+        return $j($command);
+    }
+
     public function testPreparesRequestsWithContentType()
     {
         $request = $this->getRequest('foo', ['baz' => 'bar']);
@@ -98,6 +106,18 @@ public function testPreparesRequestsWithContentType()
         );
     }
 
+    public function testPreparesRequestsWithEndpointWithPath()
+    {
+        $request = $this->getPathEndpointRequest('foo', ['baz' => 'bar']);
+        $this->assertEquals('POST', $request->getMethod());
+        $this->assertEquals('http://foo.com/bar', (string) $request->getUri());
+        $this->assertEquals('{"baz":"bar"}', (string) $request->getBody());
+        $this->assertEquals(
+            'application/json',
+            $request->getHeaderLine('Content-Type')
+        );
+    }
+
     public function testPreparesRequestsWithBlobButNoForcedContentType()
     {
         $request = $this->getRequest('bar', ['baz' => 'bar']);