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 on Taiwan, signed in June 2013 but never ratified by the Legislative Yuan of Taiwan, aimed at liberalizing trade in services between the two economies. Under the terms of the treaty, service industries such as banking, healthcare, tourism, film, telecommunications, and publishing would be opened to investment and businesspeople would be able to obtain indefinitely renewable visas for the other territory. It would become easier for businesses to set up offices and branches in the other territory and for large stakes in businesses to be sold to the other party's investors.

The CSSTA is one of two planned follow-up treaties to the 2010 Economic Cooperation Framework Agreement. The other, the Cross-Strait Goods Trade Agreement, has not yet been negotiated.

In March 2014 the Sunflower Student Movement began. The movement opposed the CSSTA, protesting the agreement on the grounds that the Kuomintang (KMT) leadership in Taiwan negotiated and attempted ratification through undemocratic processes.