An adapter for windshield wiper arms which is used to couple a wiper arm to a wiper blade is provided. The adapter is capable of accommodating a variety of wiper arm types known as the hook, bayonet and pin type wiper arms, and even the different size hook type wiper arms. Further, the adapter has vertical wings with protrusions formed at outer surfaces thereof so as to thereby reduce a friction caused between the adapter and the adapter accommodating portion of the wiper blade, and a plurality of embossings formed at inner walls of vertical wings so as to thereby prevent the hook type wiper arm from vibrating.