CJ7 (Chinese: 長江七號; Cantonese Yale: Cheung gong chat hou; lit. 'Yangtze 7') is a 2008 Hong Kong–Chinese science fiction comedy-drama film co-written, co-produced, starring, and directed by Stephen Chow in his final film acting performance, before he became a fulltime filmmaker. The film was released theatrically in Hong Kong on January 31, 2008.

In August 2007, the film was given the title CJ7, a play on China's successful Shenzhou crewed space missions—Shenzhou 5 and Shenzhou 6. It was previously known by a series of working titles including Alien and most notably A Hope. CJ7 was filmed in Ningbo, in the Zhejiang province of China.