Ernesti is a surname. Notable people with the surname include:
Johann August Ernesti (1707–1781), German Rationalist theologian and philologist Johann Christian Gottlieb Ernesti (1756–1802), German classical scholar Johann Heinrich Ernesti (1652–1729), German philosopher, Lutheran theologian, Latin classicist and poet
See also Ernesti Rikhard Rainesalo (1864–1929), Finnish politician