| Birth Date: | 1939 5, df=y |
| Birth Place: | Bodegraven, the Netherlands |
| Height: | 1.68m (05.51feet) |
| Weight: | 56kg (123lb) |
| Sport: | Artistic gymnastics |
| Club: | GV Bodegraven |
| Show-Medals: | yes |
Maria Teuntje "Ria" van Velsen (born 18 May 1939) is a retired Dutch artistic gymnast who participated in the 1960 Summer Olympics. She took part in all events, with the best achievement of 14th place in the team all-around competitions. She is not related to the Dutch swimmer Ria van Velsen who also competed at the 1960 Games.[1] After marriage to Thijs Rietveld in 1961 she was often credited as Ria Rietveld.