Index: src/js/_enqueues/admin/edit-comments.js
===================================================================
--- src/js/_enqueues/admin/edit-comments.js	(revision 43597)
+++ src/js/_enqueues/admin/edit-comments.js	(working copy)
@@ -592,6 +592,15 @@
 			}
 		});
 
+		// Allow users to use Ctrl/Cmd+Enter to submit comment
+		$('#replycontent', row).keydown(function (e) {
+			if (( e.metaKey || e.ctrlKey ) && e.keyCode === 13) {
+				commentReply.send();
+				e.preventDefault();
+				return false;
+			}
+		});
+
 		// add events
 		$('#the-comment-list .column-comment > p').dblclick(function(){
 			commentReply.toggle($(this).parent());
Index: src/js/_enqueues/lib/comment-reply.js
===================================================================
--- src/js/_enqueues/lib/comment-reply.js	(revision 43597)
+++ src/js/_enqueues/lib/comment-reply.js	(working copy)
@@ -85,6 +85,25 @@
 	}
 
 	/**
+	 * Submits the comment form.
+	 *
+	 * @param e          The triggered event.
+	 * @param textareaId The comment form textarea id.
+	 *
+	 * @return {boolean}
+	 */
+	function submitForm( e, textareaId ) {
+		if ( ( e.metaKey || e.ctrlKey ) && e.keyCode === 13 ) {
+			var textarea    = document.getElementById( textareaId ),
+				commentForm = document.getElementById( textarea.form.id );
+
+				document.createElement( 'form' ).submit.call( commentForm );
+			e.preventDefault();
+			return false;
+		}
+	}
+
+	/**
 	 * Return all links classed .comment-reply-link.
 	 *
 	 * @since 5.0.0
@@ -317,6 +336,7 @@
 	}
 
 	return {
+		submitForm: submitForm,
 		init: init,
 		moveForm: moveForm
 	};
Index: src/wp-includes/comment-template.php
===================================================================
--- src/wp-includes/comment-template.php	(revision 43597)
+++ src/wp-includes/comment-template.php	(working copy)
@@ -2297,7 +2297,7 @@
 	$fields   = apply_filters( 'comment_form_default_fields', $fields );
 	$defaults = array(
 		'fields'               => $fields,
-		'comment_field'        => '<p class="comment-form-comment"><label for="comment">' . _x( 'Comment', 'noun' ) . '</label> <textarea id="comment" name="comment" cols="45" rows="8" maxlength="65525" required="required"></textarea></p>',
+		'comment_field'        => '<p class="comment-form-comment"><label for="comment">' . _x( 'Comment', 'noun' ) . '</label> <textarea id="comment" name="comment" cols="45" rows="8" maxlength="65525" required="required"  onkeydown="return addComment.submitForm( event, \'comment\' )"></textarea></p>',
 		/** This filter is documented in wp-includes/link-template.php */
 		'must_log_in'          => '<p class="must-log-in">' . sprintf(
 			/* translators: %s: login URL */