Yennai Arindhaal (transl. If You Know Me) is a 2015 Indian Tamil-language action thriller film written and directed by Gautham Vasudev Menon and produced by A. M. Rathnam. The film stars Ajith Kumar, Trisha Krishnan, Anushka Shetty and Arun Vijay in the lead roles, while Vivek, Anikha, Parvathy Nair, Ashish Vidyarthi, Suman and Avinash Yelandur appear in supporting roles. It is also the final film of Menon's police trilogy after Kaakha Kaakha and Vettaiyaadu Vilaiyaadu. The film revolves around a former police officer's battle to protect his step-daughter from his arch-enemy.

Menon decided to finalise the script in October 2013 with Shridhar Raghavan and Thiagarajan Kumararaja as the script consultants. Principal photography was launched on 9 April 2014, and its first schedule took place in Chennai on 11 April 2014 within 12 days. The second schedule of the film took place in May 2014, where the filming took place in Chennai, Hyderabad, Rajasthan, Sikkim and a few parts of Malaysia. The music was composed by Harris Jayaraj, reuniting with Menon after Vaaranam Aayiram (2008). Dan Macarthur handled the cinematography, while Anthony edited the film.

Yennai Arindhaal was released theatrically on 5 February 2015 to positive reviews from critics. At the 63rd Filmfare Awards South, the film was nominated under five categories including Best Actor for Ajith Kumar, Best Supporting Actor for Arun Vijay, Best Music Director for Harris Jayaraj and Best Lyricist for Thamarai. The film was nominated for six categories under the 5th South Indian International Movie Awards, in which Arun Vijay won the award for Best Actor in a Negative Role – Tamil.