The Cross-Strait Service Trade Agreement, commonly abbreviated CSSTA and sometimes alternatively translated Cross-Strait Agreement on Trade in Services, is a treaty between the People's Republic of China and the Republic of China (Taiwan) that was signed in June 2013. However, it was never ratified by the Taiwanese legislature due to opposition from the Sunflower Student Movement, which rejected the CSSTA on the grounds that the Kuomintang (KMT) leadership in Taiwan negotiated and attempted ratification of the treaty in an undemocratic way.

The Sunflower Student Movement is associated with a protest movement driven by a coalition of students and civic groups that came to a head between March 18 and April 10, 2014, in the Legislative Yuan and, later, also the Executive Yuan of Taiwan. The activists protested the passing of the Cross-Strait Service Trade Agreement (CSSTA) by the then ruling Kuomintang (KMT) at the legislature without a clause-by-clause review.