| Birth Date: | 3 January 1955 |
| Birth Place: | Beverwijk, Netherlands |
| Height: | 1.67m (05.48feet) |
| Weight: | 54kg (119lb) |
| Sport: | Artistic gymnastics |
| Club: | Klimop, Heiloo |
| Show-Medals: | yes |
Anna Maria "Ans" Dekker (born 1 March 1955) is a former artistic gymnast from the Netherlands who competed at the 1972 and 1976 Summer Olympics in all artistic gymnastics events. Her best achievement was 9th place in the team all-around in 1972.
She is wife of Sjaak Pieters, aunt of Amy Pieters and sister-in-law of Peter Pieters, all of whom are Olympic cyclists.