Murattu Kaalai (transl. Raging Bull) is a 1980 Indian Tamil-language action film directed by S. P. Muthuraman, and written by Panchu Arunachalam. The film stars Rajinikanth, Rati Agnihotri, Sumalatha and Jaishankar. It revolves around Kaalaiyan, an honourable villager who, despite being wealthy, chooses to live modestly while Sundaravelu, a less honourable man from the neighbouring village, tries to grab Kaalaiyan's land.

Murattu Kaalai was the first film for Rajinikanth with AVM Productions, and the company's re-entry into Tamil cinema after a long sabbatical. It was released on 20 December 1980 and became an Industry Hit Blockbuster commercial success. The film was also instrumental in establishing Rajinikanth as both an action hero and superstar. It was remade again in Tamil under the same title and released in 2012.