Marcelo Birmajer (born November 29, 1966, in Buenos Aires) is an Argentine Jewish author.

Birmajer's work usually revolves around the Porteño neighbourhood of Once and its colorful inhabitants.

He also addresses Jewish issues such as synagogue attendance, Bar Mitzvahs, and the ever present alternative to immigrate to Israel.

Many of Birmajer's works have clear autobiographical lines, presenting a main character who is himself a writer.

His brother, Rabbi Reuven Eduardo Birmajer, was assassinated by Palestinian terrorists in Jerusalem on 23 December 2015.