diff --git a/app/code/Magento/Sales/Model/Order.php b/app/code/Magento/Sales/Model/Order.php
index 1d1b926a1a24c..b9d66818e8f9c 100644
--- a/app/code/Magento/Sales/Model/Order.php
+++ b/app/code/Magento/Sales/Model/Order.php
@@ -559,7 +559,7 @@ public function setCanSendNewEmailFlag($flag)
      */
     public function loadByIncrementId($incrementId)
     {
-        return $this->loadByAttribute('increment_id', $incrementId);
+        return $this->loadByAttribute('increment_id', (string) $incrementId);
     }
 
     /**
@@ -573,7 +573,7 @@ public function loadByIncrementIdAndStoreId($incrementId, $storeId)
     {
         $orderCollection = $this->getSalesOrderCollection(
             [
-                'increment_id' => $incrementId,
+                'increment_id' => (string) $incrementId,
                 'store_id' => $storeId
             ]
         );