Muhammad Cassim Siddi Lebbe (11 June 1838 – 5 February 1898), who was also known by the name Mukammatu Kacim Cittilevvai, was a prominent figure in British Ceylon, modern-day Sri Lanka.

The Lebbe family claimed ancestry from Arabs who settled on the western coast of Ceylon and later penetrated the Kandyan District, where his father was born.

Proficient in Arabic, he studied many significant works of Islamic scholars and possessed religious knowledge that surpassed that of the local Ulema of his time.

The educational movement in Colombo, which he initiated with Wapchi Marikar, necessitated his presence in the city, although he occasionally visited his hometown in Kandy.

He used the medium of newspaper articles, books, and speeches to induce the Muslim community to make an attempt to uplift themselves from the backward condition they were in.