| Udo Poser | |
| Birth Date: | 21 August 1947 |
| Birth Place: | Hildburghausen, Germany |
| Height: | 1.86m (06.1feet) |
| Weight: | 87kg (192lb) |
| Sport: | Swimming |
| Club: | ASK Vorwärts Rostock |
| Show-Medals: | yes |
Udo Poser (born 21 August 1947) is a German former swimmer. He competed at the 1968 and 1972 Summer Olympics and won a bronze medal in the 4 × 100 m freestyle relay in 1972 by swimming for the East Germany team in the preliminary round. He finished in fifth and sixth place in the 4 × 100 m freestyle relay in 1968 and in the 4 × 200 m freestyle relay in 1972, respectively, whereas individually he failed to reach the finals in the 200 m and 400 m freestyle.
He competed at two European championships in 1966 and 1970 and earned eight medals, including three gold medals, and set one world record in the 4 × 100 m freestyle relay in 1970. Between 1969 and 1971 he won six national titles in the 100 m and 200 m butterfly events.