diff --git a/vendor/magento/module-sales/Model/Service/CreditmemoService.php b/vendor/magento/module-sales/Model/Service/CreditmemoService.php
index 6a9826d0c22..f19f4063c7e 100644
--- a/vendor/magento/module-sales/Model/Service/CreditmemoService.php
+++ b/vendor/magento/module-sales/Model/Service/CreditmemoService.php
@@ -148,7 +148,7 @@ class CreditmemoService implements \Magento\Sales\Api\CreditmemoManagementInterf
         \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo,
         $offlineRequested = false
     ) {
-        $this->validateForRefund($creditmemo);
+        $this->validateForRefund($creditmemo, (bool)$offlineRequested);
         $creditmemo->setState(\Magento\Sales\Model\Order\Creditmemo::STATE_REFUNDED);
 
         $connection = $this->getResource()->getConnection('sales');
@@ -183,11 +183,14 @@ class CreditmemoService implements \Magento\Sales\Api\CreditmemoManagementInterf
      * Validates if credit memo is available for refund.
      *
      * @param \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo
+     * @param bool $offlineRequested
      * @return bool
      * @throws \Magento\Framework\Exception\LocalizedException
      */
-    protected function validateForRefund(\Magento\Sales\Api\Data\CreditmemoInterface $creditmemo)
-    {
+    protected function validateForRefund(
+        \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo,
+        bool $offlineRequested = false
+    ) {
         if ($creditmemo->getId() && $creditmemo->getState() != \Magento\Sales\Model\Order\Creditmemo::STATE_OPEN) {
             throw new \Magento\Framework\Exception\LocalizedException(
                 __('We cannot register an existing credit memo.')
@@ -214,6 +217,16 @@ class CreditmemoService implements \Magento\Sales\Api\CreditmemoManagementInterf
                 )
             );
         }
+
+        if (!$offlineRequested && $creditmemo->getInvoice() && (float)$creditmemo->getBaseGrandTotal() <= 0.0) {
+            $payment = $creditmemo->getOrder()->getPayment();
+            $method = $payment->getMethodInstance();
+            if (!$method->isOffline()) {
+                throw new \Magento\Framework\Exception\LocalizedException(
+                    __('Online refund amount must be greater than zero.')
+                );
+            }
+        }
         return true;
     }
 
diff --git a/vendor/magento/module-sales/i18n/en_US.csv b/vendor/magento/module-sales/i18n/en_US.csv
index be0a050b8d2..37dc341dadf 100644
--- a/vendor/magento/module-sales/i18n/en_US.csv
+++ b/vendor/magento/module-sales/i18n/en_US.csv
@@ -823,3 +823,4 @@ If set YES Email field will be required during Admin order creation for new Cust
 "User is not authorized to edit comment.","User is not authorized to edit comment."
 "Cannot edit comment.","Cannot edit comment."
 "Update Comment","Update Comment"
+"Online refund amount must be greater than zero.", "Online refund amount must be greater than zero."