Barlaam may refer to:
- Barlaam of Seminara, Italian scholar and theologian (c.1290–1348), also known as Barlaam of Calabria, whose name as a layman was Bernardo Massari, brought an accusation of heresy against Gregory Palamas for the latter's defence of Hesychasm (the Eastern Orthodox Church's mystical teaching on prayer)
- Saint Barlaam, eventual companion of St. Josaphat of India
- Barlaam of Khutyn
- Barlaam of Kiev, saint in the Russian Orthodox Church