Mulan Joins the Army (simplified Chinese: 木兰从军; traditional Chinese: 木蘭從軍; pinyin: Mùlán cóngjūn), is a 1939 Chinese historical war film. It is one of several film adaptations of the Hua Mulan (花木兰) legend, which have included two silent versions: Hua Mulan Joins the Army (1927) by Tianyi Film Company, and a less successful Mulan Joins the Army (1928) produced by China Sun Motion Picture Company.

The film, described as a musical comedy, was directed by Richard Poh (Bu Wancang) and stars Nancy Chan (credited as Chen Yunshang) as the title character, a young woman who disguises herself as a man in order to take her father's place in the army. The success of the movie was evident by the record-breaking running time of 83 days. The screenplay by Ouyang Yuqian, was produced in Shanghai by the Hwa Cheng Studio (華成製片廠), a subsidiary of the Xinhua Film Company.