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.