Sakakibara Yasumasa (榊原 康政, 1548 – June 19, 1606) was a Japanese daimyō of the late Sengoku period through early Edo period, who served the Tokugawa clan. As one of the Tokugawa family's foremost military commanders, he was considered one of its "Four Guardian Kings" (shitennō 四天王) along with Sakai Tadatsugu, Honda Tadakatsu and Ii Naomasa. His court title was Shikibu-Shō (式部大輔).