毕宿五 （α Tau / 金牛座α）为毕宿第五星，是金牛座的主星，距离地球65光年。其光谱与光度分类属于K5 III型，呈橙色，在地球上的视星等为0.86，是夜空中的亮星之一。

毕宿五的直径约为5300万公里，是太阳直径的38倍。由于其内里的氢已经耗尽，毕宿五已由主序星演变为红巨星，靠燃烧氦来继续发光发热。

毕宿五有一个伴星，是一个视星等达11等的白矮星，肉眼不能看见，只能够用望远镜来观测。

1997年，人们透过观测，认为毕宿五可能有一个行星（也可能是棕矮星）存在，其质量约为木星的十一倍，距离毕宿五只有1.3天文单位。

Aldebaran (α Tau, α Tauri, Alpha Tauri) is an orange giant star located about 65 light years away. It is the brightest star in the zodiac constellation of Taurus. It varies slowly in brightness between magnitude 0.75 and 0.95, which means it is usually the fourteenth brightest star in the nighttime sky. The name Aldebaran is Arabic (الدبران al-dabarān) and means "the Follower", presumably because it rises near and soon after the Pleiades. It is likely that Aldebaran hosts a planet several times the size of Jupiter.