Operation Yellowbird (Chinese: 黃雀行動) or Operation Siskin was a British Hong Kong–based operation to help the Chinese dissidents who participated in the Tiananmen Square protests of 1989 to escape arrest by the Chinese government by facilitating their departure overseas via Hong Kong. Western intelligence agencies such as Britain's Secret Intelligence Service (SIS a.k.a. MI6) and the U.S. Central Intelligence Agency (CIA) were involved in the operation. Other contributors included politicians, celebrities, business people and triad members from Hong Kong—forming the "unlikely" alliance which sustained the operation for most of its duration.
The operation began in late June 1989, following the issuing of an order by the Beijing Municipal Public Security Bureau on 13 June 1989 to apprehend the leaders of the Beijing Students' Autonomous Federation who were on the run. The operation continued until 1997, which coincides with the year that British Hong Kong transitioned to independence. Yellowbird successfully helped more than 400 dissidents, who were smuggled through Hong Kong, and then onwards to Western countries. Notable escapees include Wu'erkaixi, Chai Ling, Li Lu, Feng Congde, Chen Yizi, and Su Xiaokang. Three Hong Kong–based activists were arrested by the Chinese authorities, but later released after the intervention of the Hong Kong government.