N.Viswanathan (18 July 1929 – 17 November 2010), popularly known as Calcutta Viswanathan in the Tamil film industry, was an Indian actor and academic.
A Tamilian by birth, he moved to Calcutta (now Kolkata) at a young age and taught English at St.
Xavier's College, Calcutta for more than 40 years.
Viswanathan was also a well-known public speaker.
He made his acting debut in Mrinal Sen's Punascha and continued to act in Bengali films.
In a career that spanned 40 years, Viswanathan appeared in nearly 100 films in Bengali, Tamil and English.
He was a member several theatre groups and also formed the "Calcutta Players", an acting troupe.