János Wenk (April 24, 1894 - October 17, 1962) was a Hungarian water polo player and backstroke swimmer who competed in the 1912 Summer Olympics and in the 1924 Summer Olympics.
Born in Csaca, He was part of the Hungarian water polo team, which competed in the 1912 tournament as well as twelve years later in the 1924 tournament. At the 1928 tournament he was a reserve player and did not compete in a match.
In 1912 he also competed in the 100 metre backstroke event, but he was eliminated in the first round. He died in Budapest.