Samuel Castriota (November 2, 1885 – July 8, 1932) was an Argentinian pianist, guitarist and composer. He is the composer of the tango Mi noche triste, among other works.

Born in Buenos Aires, Castriota spent his childhood in the nearby town of San Miguel where he learned to play the guitar "by ear" that is without reading music. He returned to Buenos Aires at age 16 and began performing in small ensembles while also learning to play the piano.

He won a major prize in the lottery, and moved away from music toward establishing a hairdressing business. Eventually, however, he returned to his musical hobby and played piano in a trio that included himself, Vicente Loduca on bandoneon and Francisco Canaro on violin.

In the middle of the first decade of the twentieth century, Castriota released an instrumental tango, and Pascual Contursi provided lyrics. Carlos Gardel brought the names of Castriota and Contursi to public attention. Contursi had added lyrics to tangos composed by other artists, but not with the success that came from the collaboration with Castriota on Mi noche triste.

Castriota continued to direct his orchestra, alternating as pianist, and composing new pieces. However, those new pieces never came close to having the impact of Mi noche triste. He died in Buenos Aires on July 8, 1932.