Nak (Thai: นาค) is a Thai animated dark fantasy horror film that was released on April 3, 2008 and aired on TV in Thai PBS Kids.

The story is based on ghosts of the folklore of Thailand, who in this movie shed their sinister reputation and are the heroes. Nak, its central character, is based on the figure of Mae Nak, a Thai female spirit that has a baby and can stretch her arms. Nak's striking fuchsia-colored hair and eyes in this movie are a departure from her alleged looks in traditional lore though. Other spirits familiar to Thai people that appear in this movie are Phi Hua Kat, Krahang, Krasue, Phi Am, Nang Tani, Nang Takian and Phi Phong.

Ghosts from other backgrounds such as Phi Yipun, the scary woman with long, stringy black hair wearing a white gown, a well-known vengeful ghost (onryō) from Japanese horror films based on the Yotsuya Kaidan story, also have a role in the Nak movie.