Decroix (French pronunciation: [dəkʁwa]) is a surname. Notable people with the surname include:
- Emile Decroix (1904–1967), Belgian racing cyclist
- Éric Decroix (born 1969), French footballer
- Julien Decroix, better known as Soan, (born 1981), French singer-songwriter
- Lieselot Decroix (born 1987), Belgian road cyclist
- Marjolein Decroix (born 1992), Belgian alpine skier