Leonid Isaakovich Mandelshtam (Леонид Исаакович Мандельштам) (May 4, 1879 - November 27, 1944) was a Russian physicist.
Madelshtam was born in Mahilyow (Mogilev, Mahileu), Russian Empire (now Belarus).
He was mentor to a Nobel Laureate in Physics Igor Yevgenyevich Tamm in science and life.
Mandelshtam died in Moscow, Soviet Union (now Russia).