食指，学名为示指（index finger），是第二只手指，位于拇指与中指之间，长度与环指相若。

食指一词早在春秋时代的《左传》已有记载（公子宋），并衍生出「食指大动」这个成语。

The index finger, (also referred to as forefinger, pointer finger, trigger finger, digitus secundus, digitus II, and many other terms), is the first finger and the second digit of a human hand. It is located between the first and third digits, between the thumb and the middle finger. It is usually the most dextrous and sensitive finger of the hand, though not the longest – it is shorter than the middle finger, and may be shorter or longer than the ring finger – see digit ratio.