How many words start with YI?

13, from 5 letters up to 5. All of them are on this page.

What is the highest scoring word that start with YI?

YIPPY at 15 points in Scrabble, and YIPPY at 15 in Words With Friends, because the two games score the tiles differently.

YIELD, YIKED, YIKES, YILLS, YINCE, YIPES, YIPPY, YIRDS, YIRKS, YIRRS and 3 more on this page.

13 of them: YIELD, YIKED, YIKES, YILLS, YINCE, YIPES, YIPPY, YIRDS, YIRKS, YIRRS and more.

There are 13 of them. The highest scoring is YIPPY at 15 points in Scrabble, and the set averages 10.2.

Most common words first, then the rest A to Z.

All of them: Word lists.