Lady Cop & Papa Crook (Chinese: 大搜查之女; pinyin: Da sou zha zhi nu; Cantonese Yale: Daai sau cha ji neui) is a 2008 Hong Kong crime film written and directed by Alan Mak and Felix Chong, and starring Sammi Cheng and Eason Chan. Chan plays the kingpin of a red diesel crime ring who is forced to team up and co-operate with a hot-tempered police officer (Cheng) when his son is kidnapped, thus beginning an unlikely alliance between fellow police officers and criminals.

The film marks Cheng's first feature-film role after a three-year absence from the Hong Kong cinema scene, her last film being the 2005 film Everlasting Regret. After filming, Lady Cop & Papa Crook's theatrical release date was delayed several times, due to the film not meeting Chinese censorship standards, which resulted in several scenes being reshot. The film later received a confirmed Hong Kong release date of 1 January 2009 in Hong Kong and Singapore.