The Third Wife (Vietnamese: Vợ ba) is a 2018 Vietnamese costume drama film written and directed by Ash Mayfair, in her feature debut. Set in the 19th century, it follows a 14-year-old girl who becomes the third wife to a landowner in rural northern Vietnam.

The film premiered at the Toronto International Film Festival in September 2018, where it won the Network for the Promotion of Asian Cinema (NETPAC) Award. It also won the TVE-Another Look Award at the San Sebastian International Film Festival and the Gold Hugo for New Directors at the Chicago International Film Festival in October 2018.

The film was nominated for Best Cinematography, Best Editing, and Someone to Watch Award at the 35th Independent Spirit Awards.

In 2020 Mayfair released a re-worked version of the film called Between Shadow and Soul. The re-worked film used the same footage from the original shoot but reconfigured in black and white and with no dialogue and a new soundtrack.