Benjamin Blumenfeld (24 May 1884, Volkovysk – 5 March 1947, Moscow) was a Russian chess master.
He was born in Volkovysk, Suwałki Governorate, Russian Empire (today Vawkavysk, Belarus). In 1905/06 he tied for second/third with Akiba Rubinstein, behind Gersz Salwe, in St. Petersburg (the fourth Russian championship). In 1907 he tied for second/third with Georg Marco, behind Mikhail Chigorin, in Moscow.
In 1920 he took eighth in Moscow (Russian Chess Olympiad, 1st URS-ch). The event was won by Alexander Alekhine. In 1925 he tied for second/third with Boris Verlinsky, behind Aleksandr Sergeyev, in the Moscow championship.
He invented the Blumenfeld Gambit (1.d4 Nf6 2.c4 c5 3.d5 e6 4.Nf3 b5).