Petros Heronimosi Adamian (Armenian: Պետրոս Հերոնիմոսի Ադամեան, December 21, 1849, Istanbul – June 3, 1891, Istanbul, Ottoman Empire) was an outstanding Armenian actor, poet, writer, artist and public figure. According to Russian critics, his interpretations of Hamlet and Othello put Adamian's name among the best tragedians of the world.

He started his artistic career at the age of seventeen, in the play "William the Conqueror." After a first period in his career where he gradually won recognition in the theater groups of Constantinople, in 1879 he was hired by the Armenian Theater Board of Tiflis and the golden period of his career started afterwards in the Caucasus. He would abandon the historical plays and the French melodramas to enter the world of Shakespeare. Since 1879 he performed in Baku, Shushi, Alexandropol, Tiflis. In the 1880s, when the Ottoman Turkish reaction "held the national minorities in scorn", Adamian had an artistic tour in foreign (Russian and Ukrainian) cities, acting both in Armenian and French languages. In 1887 a Russian theatrical critic wrote about Adamian in "Odessky Vestnik": "Not Salvini, not Rossi, not Possart, not Barna, and finally, no world-famous actor has given us such a pure and perfect Hamlet as P. Adamian did." In 1888 he returned to Constantinople. Among his best roles of that period: King Lear, Arbenin (Lermontov's "Masquerade"), Khlestakov (Gogol's "Revisor"), Mikael (Sundukian's "One more victim"), etc. Being a "great Shakespearean actor" and the first Armenian scientific researcher of William Shakespeare plays, in 1887 he published the study "Shakespeare and the Sources and Criticism of His Tragedy Hamlet." He also made translations from Shakespeare, Victor Hugo, Semyon Nadson, and Nikolai Nekrasov.

Adamian suffered from a throat cancer for the last two years of his life. He died in the St. Nicholas Russian hospital of Constantinople.

Siranush, Hovhannes Abelian, Vahram Papazian, and other Armenian actors continued Adamian's theatrical tradition.

The Armenian Drama Theatre of Tbilisi is named after Adamian.