This is a matter to discuss with your physician because the answer may rely on your particular condition. For many people, yes it does often help, and the following information can help inform your discussion with them.
While it seems strange to add more acid to an acid reflux problem, some theories suggest that reflux is caused by too little stomach acid, which prevents the “valve” (LES) at the top of the stomach from closing properly. Taking a diluted tablespoon of ACV can signal that valve to shut. On the other hand, if you have an ulcer or an inflamed esophagus, vinegar will make it worse.