Grand Masti (transl. Grand fun), also referred to as Masti 2, is a 2013 Indian Hindi-language sex comedy film directed by Indra Kumar and produced by Ashok Thakeria. The film is a sequel to the 2004 film Masti, and the second installment of the Masti (film series). It features Riteish Deshmukh, Vivek Oberoi and Aftab Shivdasani reprising their roles from the original, but the story is new and does not continue from the earlier installment. The film also stars Bruna Abdullah, Karishma Tanna, Sonalee Kulkarni, Kainaat Arora, Maryam Zakaria and Manjari Fadnis in key roles.

Grand Masti was released on 13 September 2013, and was one of the highest-grossing Bollywood films of 2013. The film received largely negative responses from critics because of its extreme sexual nature, but it was a box office success. Grand Masti was the highest grossing A-rated Bollywood film in India, until it was overtaken by Kabir Singh in 2019.

The film entered Bollywood's 100 crore club and was declared a Super Hit by Box Office India. The third installment of Masti (film series), Great Grand Masti was released on 15 July 2016.