Secret (traditional Chinese: 不能說的·秘密; simplified Chinese: 不能说的·秘密; pinyin: Bùnéng shuō de·mìmì; lit. 'The Secret That Cannot Be Told') is a 2007 Taiwanese film. It is the directorial debut feature film of Taiwanese musician Jay Chou, who also stars as the male lead and co-wrote the film. In addition to himself, the film also stars Gwei Lun-mei and Anthony Wong. Filming was conducted at Tamkang High School, New Taipei City, Taiwan, which is also the alma mater of Jay Chou. The budget was about NT$65 million.

In 2007, it received six nominations at the 44th Golden Horse Awards and won Outstanding Taiwanese Film of the Year, Best Original Song for "Secret" ("不能說的祕密") and Best Visual Effects. It was also nominated for Best Asian Film at the 27th Hong Kong Film Awards in 2008.

In 2015, the film won the 1st place in the vote of "The movie that most wants to be review in the cinema" in South Korea, and it was re-released in South Korea.

In 2016, an adapted brand new stage musical with same name was jointly produced by US Broadway and China Broadway.