| Thea Belmer | |
| Birth Date: | 1941 |
| Birth Place: | Amsterdam |
| Residence: | Wormer |
| Discipline: | WAG |
| Level: | Senior International Elite |
| Club: | KDO Amsterdam |
| Retired: | 1966 |
| Show-Medals: | yes |
Thea Belmer (born 1941, Amsterdam) is a former artistic gymnast.
Belmer had her most successful year in 1963, when in April she won a gold medal on uneven bars and a silver medal on vault at the 1963 European Championships and in December won the national championships.[1] At the world championships in Dortmund in 1966, she was a member of the Dutch team, that came in 14th of 22 teams.
Belmer married Piet Uijtendaal on 9 December 1966 in Amsterdam, after which she retired from competitive gymnastics and moved to live in Wormer.[2]