John "Marcus" Vaz (born 26 April 1956) is an Indian singer, playwright, theatre director, and actor who works on the Konkani stage.

Starting his professional career as a child artist, he first sang for C. Alvares in his tiatr Kednam Udetolo To Dis (1967).

Around the age of 20, Vaz moved to Kuwait where he discovered many professional and popular tiatrists like Xavier Gomes.

[4] In 1980, Vaz, Xavier Gomes, and Cajetan de Sanvordem formed a trio in Kuwait known as Cajetan-Marcus-Xavier.

Much of his compositions would typically remain with his fellow artists like Xavier, as Vaz doesn't usually keep the written work of his songs.

They would perform together as a quartet or trio, although their involvement isn't regular due to their busy tiatr schedules, which can clash with each other.

When Vaz brought his father on stage at the end of the song, the audience understood the true meaning, leading to a round of applause.

[4] As of 2012, some of the popular tiatrs Vaz has written include Mutt Bhor Mati, Rogtacho Fator, and Rogtak Rogot, among others.

He maintains a close friendship with Konkani singer Xavier Gomes, his fellow trio member from the Cajetan-Marcus-Xavier fame.

[citation needed] Vaz's sisters Felez and Maxie are also involved in khell tiatr productions as stage actresses.