Kothamangalam Subbu (born S. M. Subramanian, 10 November 1910 – 15 February 1974)[1] was an Indian poet, lyricist, author, actor and film director based in Tamil Nadu.

Subbu directed the epic film Avvaiyar in which the great artiste of those days Smt K. B. Sundarambal played the lead role.

Subbu, with his wife Sundari Bai, played a minor role in the movie as the husband of an incorrigible lady who refuses to serve Avvaiyar food.

[citation needed] As a writer Subbu's most well-known work is Thillana Mohanambal that was transformed into a popularly and critically successful Tamil movie, starring Sivaji Ganesan and Padmini.

Subbu was awarded the Padma Shri for authoring this novel, which originally appeared as a weekly serial in the Anantha Vikatan.

He authored Rao Bahadur Singaram, Bandanallur Bama, Ponnivanathu Poonguyil, Miss Radha, and Manju Virattu (a collection of short stories).