小指，又称小拇指、尾指，是五指里的最后一只手指，长度与拇指相若，但粗细则是五指中最细的一只，有三个关节。在很多国家，「勾小指」有二人互相承诺、约定的意思。

The pinky, or pinkie in Scottish English (from the Dutch word pink, "little finger"), or fifth digit in medicine, is the most ulnar and usually smallest finger of the human hand, opposite the thumb, next to the ring finger.