Istomin (masculine, ) or Istomina (feminine, ) is a Russian surname. Notable people with the surname include:
Avdotia Istomina (1799–1848), Russian ballerina Denis Istomin (born 1986), Uzbekistani tennis player Denis Istomin (ice hockey) (born 1987), Russian ice hockey player Eugene Istomin (1925–2003), American pianist Ivan G. Istomin (1917—1988) — Nenets and Komi author Karina Istomina (born 1994), Russian disk jockey, blogger, and model Kateryna Istomina (born 1994), Ukrainian paralympic swimmer Marta Casals Istomin (born 1937), Puerto Rican musician Vladimir Istomin (1809–1855), Russian admiral Yuriy Istomin (1944–1999), Ukrainian soccer player