Mark Aronovich Naimark (Russian: Марк Аронович Наймарк) (December 5, 1909-December 30, 1978) was a Soviet mathematician.
He was born in Odessa, Russian Empire (today's Ukraine) into a Jewish family and died in Moscow, USSR. He received his PhD in 1943 from the Steklov Institute of Mathematics.
He is known for e.g.
* the Gelfand–Naimark theorem;
* Unitary representations of the classical group (with I. M. Gelfand, 1950)
(all the above books were written in Russian)
* Naimark's problem
* Mark Naimark at the Mathematics Genealogy Project