Euphemia F. Vsevolozhskaya (1630-1657), was a Russian noble, the fiancee of Tsar Alexis of Russia.
Euphemia was chosen to be the future bride of the tsar in 1647, and brought to the imperial court. However, shortly after having been elected, she fainted. Due to political intrigues at court, she was disqualified as tsarina after having been diagnosed as an epileptic and exiled.