Leo is an action thriller film directed by Lokesh Kanagaraj, who co-wrote it with Rathna Kumar and Deeraj Vaidy. It is produced by S. S. Lalit Kumar of Seven Screen Studio while Jagadish Palanisamy serves as co-producer. The film stars Vijay and Trisha, alongside Sanjay Dutt, Arjun Sarja, Gautham Vasudev Menon, Mansoor Ali Khan and Mysskin.

The film was officially announced in January 2023 under the tentative title Thalapathy 67, as it is Vijay's 67th film as a lead actor, and the title of the film was announced a few days later. Principal photography commenced the same month in Chennai along with a sporadic schedule in Kashmir, which was again followed by another schedule held at the former location, and wrapped by mid-July. The film has music composed by Anirudh Ravichander, cinematography handled by Manoj Paramahamsa and editing by Philomin Raj.