Saiful Islam Khan (known as Hayat Saif; 16 December 1942 – 13 May 2019) was a twentieth century modern Bengali poet and literary critic from Bangladesh.
A career bureaucrat, he retired in 2000 and since then was engaged in the corporate private sector and divided his time in World Scouting and literary and artistic pursuits.
He has been translated in English and Spanish and, in Bangladesh, is generally acclaimed as an intellectual interpreter of contemporary life and culture.
Saif assumed this pen name in 1961 when contributing to literary journals.
In 2005, he was awarded the 305th Bronze Wolf.
He was awarded Ekushey Padak in 2018 for his contribution in language and literature.