Kuaiji (Chinese: 會稽/会稽, romanized K'uai-chi in Wade–Giles), also spelled Guiji, is an old name of Shaoxing.
It may also refer to:
- Mount Xianglu near Shaoxing, formerly known as Mount Kuaiji
- Kuaiji Mountains, south of Shaoxing
- Kuaiji Commandery, a historical commandery around the mountain
- Suzhou, the initial capital of the commandery
- Kuaiji County, a former county around Shaoxing