Istomin (Russian: Истомин, Ukrainian: Істомин) or Istomina is a surname. People with the name include:
- Denis Istomin (born 1986), Uzbekistan tennis player
- Denis Istomin (ice hockey) (born 1987), Russian ice hockey player
- Eugene Istomin (1925-2003), American pianist
- Marta Casals Istomin (born 1937), Puerto Rican musician
- Vladimir Istomin (1809-1855), Russian admiral
- Yuriy Istomin (1944-1999), Ukrainian footballer
- Ivan G. Istomin (1917—1988) — Nenets and Komi author
- Avdotia Istomina (1799–1848), Russian ballerina
- Karina Istomina (born 1994), Russian DJ, blogger and model
- Kateryna Istomina (born 1994), Ukrainian paralympic swimmer