Kuybyshev Reservoir or Kuybyshevskoye Reservoir, sometimes called Samara Reservoir and informally called Kuybyshev Sea, is a reservoir of the middle Volga and lower Kama in Chuvashia, Mari El Republic, Republic of Tatarstan, Samara Oblast and Ulyanovsk Oblast, Russia.

Valerian Vladimirovich Kuybyshev (– 25 January 1935) was a Russian revolutionary, Red Army officer, and prominent Soviet politician.