一、最惠國待遇原則
最惠國待遇原則是國際經貿關係中一項古老的原則。GATT1947第1條第1款首次在多邊貿易體製中引入了最惠國待遇原則，但其僅僅適用於貨物貿易。GATS作為第一個多邊服務貿易協定，同樣也規定了最惠國待遇原則。GATS第2條第1款規定：“關於本協定所涵蓋的任何措施，每一成員對於任何其他成員的服務和服務提供者，應立即和無條件地給予不低於其給予任何其他國家同類服務和服務提供者的待遇。”這一規定構成了GATS的核心條款。
Article Ⅱ
Most-Favored-Nation Treatment
1.With respect to any measure covered by this Agreement, each Member shall accord immediately and unconditionally to services and service suppliers of any other Member treatment no less favorable than that it accords to like services and service suppliers of any other country.
2.A Member may maintain a measure inconsistent with paragraph 1 provided that such a measure is listed in, and meets the conditions of, the Annex on Article II Exemptions.
3.The provisions of this Agreement shall not be so construed as to prevent any Member from conferring or according advantages to adjacent countries in order to facilitate exchanges limited to contiguous frontier zones of services that are both locally produced and consumed.
（一）GATS最惠國待遇原則與GATT最惠國待遇原則的區別
GATS中的最惠國待遇原則與貨物貿易領域中的最惠國待遇原則有著密切的聯係，這一點從兩者的措辭就可見一斑。但是，由於貨物貿易與服務貿易本身所存在的差別，GATS與GATT在最惠國待遇原則的適用上不可避免地會出現一些差異。
第一，The Most-Favoured-Nation Treatment in the GATS applies not only to the service, but the service provider; The Most-Favoured-Nation Treatment in the GATT only applies to the product itself. 這是由服務貿易中服務與服務提供者不可分離的客觀現狀決定的。