Aranmanai 3 (transl. Mansion 3) is an 2021 Indian Tamil-language comedy horror film written directed by Sundar C. The film stars an ensemble cast including Sundar, Arya, Raashii Khanna and Andrea Jeremiah, with Sakshi Agarwal, Vivek, Myna Nandhini, Yogi Babu, Nalini, Manobala, Sampath Raj, Baby Ovi Bhandarkar, Vincent Asokan, Madhusudhan Rao and Vela Ramamoorthy in prominent roles. It is the third instalment in the Aranmanai film series, produced by Khushbu under Avni Cinemax, with cinematography by U. K. Senthil Kumar, music composed by C. Sathya, and film editing by Fenny Oliver. The story revolves Jyothi (Khanna), who is threatened by a vengeful spirit, as she tries to discover the truth with her relative Ravi (Sundar).

The film was announced in January 2020 and shoots were scheduled to begin in February. Production and release were delayed due to the COVID-19 pandemic.

Aranmanai 3 was theatrically released on 14 October 2021, coinciding with Ayudha Puja, The film marks the posthumous release of Vivek. The film received mixed to negative reviews, with criticism aimed generic action sequences, outdated plot, the ensemble cast, villain and Arya's screen space, but Raashii Khanna's performance and the score received praise. Despite the reviews, the film was declared as a commercial success at the box office, and became the one of highest grossing and most profitable Tamil films of 2021.