一、最惠国待遇原则
最惠国待遇原则是国际经贸关系中一项古老的原则。GATT1947第1条第1款首次在多边贸易体制中引入了最惠国待遇原则，但其仅仅适用于货物贸易。GATS作为第一个多边服务贸易协定，同样也规定了最惠国待遇原则。GATS第2条第1款规定：“关于本协定所涵盖的任何措施，每一成员对于任何其他成员的服务和服务提供者，应立即和无条件地给予不低于其给予任何其他国家同类服务和服务提供者的待遇。”这一规定构成了GATS的核心条款。
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最惠国待遇原则与GATT最惠国待遇原则的区别
GATS中的最惠国待遇原则与货物贸易领域中的最惠国待遇原则有着密切的联系，这一点从两者的措辞就可见一斑。但是，由于货物贸易与服务贸易本身所存在的差别，GATS与GATT在最惠国待遇原则的适用上不可避免地会出现一些差异。
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. 这是由服务贸易中服务与服务提供者不可分离的客观现状决定的。
第二，GATS允许成员方对最惠国待遇提出保留，成员可以在一定期限内维持与最惠国待遇不相符的措施，并在GATS生效之前将其列入豁免清单（exemptions list）中。而在GATT中，除相关法定例外之外，成员方须无条件贯彻实施最惠国待遇原则的要求。
（二）GATS最惠国待遇原则的解释
1.“不低于”（no less favorable than）
对于“不低于”一词，一方面，应理解为各成员给予其他成员的待遇等同于其给予任何其他国家的待遇；另一方面，这也意味着不禁止施惠国给予任何其他成员以优于其给予任何第三国的待遇。
在“欧共体香蕉案”中，专家组指出，We find the Panel's reasoning on this issue to be less than fully satisfactory. The Panel interpreted Article Ⅱ of the GATS in the light of panel reports interpreting the national treatment obligation of Article Ⅲ of the GATT. The Panel also referred to Article ⅩⅦ of the GATS, which is also a national treatment obligation. But Article Ⅱ of the GATS relates to MFN treatment, not to national treatment. Therefore, provisions elsewhere in the GATS relating to national treatment obligations, and previous GATT practice relating to the interpretation of the national treatment obligation of Article Ⅲ of the GATT 1994 are not necessarily relevant to the interpretation of Article Ⅱ of the GATS. The Panel would have been on safer ground had it compared the MFN obligation in Article Ⅱ of the GATS with the MFN and MFN-type obligations in the GATT 1994.
Articles I and Ⅱ of the GATT 1994 have been applied, in past practice, to measures involving de facto discrimination.
The GATS negotiators chose to use different language in Article Ⅱ and Article ⅩⅦ of the GATS in expressing the obligation to provide ‘treatment no less favorable. The question naturally arises: if the GATS negotiators intended that ’treatment no less favorable should have exactly the same meaning in Articles Ⅱ and ⅩⅦ of the GATS, why did they not repeat paragraphs 2 and 3 of Article ⅩⅦ in Article Ⅱ? But that is not the question here. The question here is the meaning of ’treatment no less favorable with respect to the MFN obligation in Article Ⅱ of the GATS. There is more than one way of writing a de facto non-discrimination provision. Article ⅩⅦ of the GATS is merely one of many provisions in the WTO Agreement that require the obligation of providing ’treatment no less favorable. The possibility that the two Articles may not have exactly the same meaning does not imply that the intention of the drafters of the GATS was that a de jure, or formal, standard should apply in Article Ⅱ of the GATS. If that were the intention, why does Article Ⅱ not say as much? The obligation imposed by Article Ⅱ is unqualified. The ordinary meaning of this provision does not exclude de facto discrimination. Moreover, if Article Ⅱ was not applicable to de facto discrimination, it would not be difficult - and, indeed, it would be a good deal easier in the case of trade in services, than in the case of trade in goods - to devise discriminatory measures aimed at circumventing the basic purpose of that Article.
For these reasons, we conclude that，treatment no less favorable in Article Ⅱ:1 of the GATS should be interpreted to include de facto, as well as de jure, discrimination. We should make it clear that we do not limit our conclusion to this case. We have some difficulty in understanding why the Panel stated that its interpretation of Article Ⅱ of the GATS applied ‘in casu’.[1]
2.“同类服务和服务提供者”（like services and service suppliers）
与GATT第1条中的“同类产品”相比，这一概念更加难以确定。在乌拉圭回合谈判过程中，工作组对服务分类做了大量的工作，并根据联合国核心产品临时分类目录草拟了服务部门分类表的修订版，但这种分类在适用于GATS时仍存在许多问题，如当同类服务以不同模式提供时是否还属于“同类服务”，就很难进行界定。[2]在实践中，专家组在“欧共体香蕉案”中指出：In our view, the nature and the characteristics of wholesale transactions as such, as well as of each of the different subordinated services mentioned in the headnote to section 6 of the CPC, are ‘like’ when supplied in connection with wholesale services, irrespective of whether these services are supplied with respect to bananas of EC and traditional ACP origin, on the one hand, or with respect to bananas of third-country or non-traditional ACP origin, on the other. Indeed, it seems that each of the different service activities taken individually is virtually the same and can only be distinguished by referring to the origin of the bananas in respect of which the service activity is being performed. Similarly, in our view, to the extent that entities provide these like services, they are like service suppliers. [3]
“加拿大进口汽车案”的专家组则进一步强调说，“We agree that to the extent that the service suppliers concerned supply the same services, they should be considered ‘like’ for the purpose of this case.” [4]不过，除了是否提供相同服务之外，影响服务提供者是否相同的因素还包括许多因素，如技术力量、设备情况、业务范围、交易数额等。因此，这里的“同类服务和服务提供者”更需要结合实际的具体情况来判断，正是基于类似的考虑，GATS中并没有明确说明何为“同类服务和服务提供者”。
（三）GATS最惠国待遇的例外和豁免
1.GATS最惠国待遇的一般性例外
GATS最惠国待遇的一般性例外主要包括两种情况。第一种情况是GATS第2条第3款所规定的边境贸易例外，即任何成员可以对相邻国家授予或给予优惠，以便利仅限于毗邻边境地区的当地生产和消费服务的交换；第二种情况是经济一体化成员方之间的优惠，主要规定在GATS的第5条。除此之外，如果相关措施符合GATS第14条的一般性例外和安全例外的规定，自然也可以背离最惠国待遇的要求，这一点自不待言。
2.豁免清单
根据GATS第2条第2款，一成员可以采取与最惠国待遇不一致的措施，只要该措施已列入《关于第2条豁免的附件》（Annex on Article Ⅱ Exemptions），并符合该附件中规定的条件。在GATS谈判初期，美国主张采用有条件的最惠国待遇，认为那些不想在有关服务部门提供充分市场准入的国家不应当要求美国开放市场，应该杜绝相应的“搭便车”（free rider）现象。但服务业水平处于弱势地位的发展中国家坚决反对这种无条件的最惠国待遇，最终的结果便是双方达成妥协，即第2条第2款的豁免安排。要想获得这种豁免，一般需要列明豁免所适用的服务部门；需要援引豁免的具体措施；豁免所针对国家、期限和豁免的必要性等。此外，《关于第2条豁免的附件》还规定了最惠国待遇义务豁免的评审和终止，服务贸易理事会应对成员所给予的超过5年期的豁免进行审议，豁免的时限原则上不得超过10年。豁免期终止时，成员应通知服务贸易理事会。不过，这里的10年并不是最终的期限，而是可以延长的。从实践情况看，大多数WTO成员都宣布保留最惠国待遇豁免。
3.政府采购豁免
根据GATS第13条的规定，最惠国待遇不适用于涉及政府采购的法律、规章和要求，但这种政府采购只能是为了政府目的，用于商业转卖或服务供应中的商业销售的政府采购不在此限。此外，该条还规定成员方应该在WTO协定生效之日起2年内就GATS中的政府采购问题进行谈判。
Article ⅩⅢ
Government Procurement
1. Articles Ⅱ, ⅩⅥ and ⅩⅦ shall not apply to laws, regulations or requirements governing the procurement by governmental agencies of services purchased for governmental purposes and not with a view to commercial resale or with a view to use in the supply of services for commercial sale.
2. There shall be multilateral negotiations on government procurement in services under this Agreement within two years from the date of entry into force of the WTO Agreement.
4.弃权或免除（waiver）
根据《建立世界贸易组织协定》第9条第3款的规定，WTO部长级会议在特殊情况下可以决定免除包括GATS在内的任何多边贸易协定所施加的义务，条件是这种免除需要经3/4的成员通过。
二、透明度原则
与GATT一样，GATS同样也把透明度原则作为协定的一项基本原则。由于服务贸易本身并不经过关境，传统货物贸易中针对货物的关税、许可证、配额等边境贸易管理措施无法适用于服务贸易，服务贸易的管理职能更多地依靠国内立法，因此，国内法律、法规和规章的公开、透明就显得尤为重要。基于这种考虑，GATS第3条对协定义务实施中的透明度要求作出了以下规定。
Article Ⅲ
Transparency
1. Each Member shall publish promptly and, except in emergency situations, at the latest by the time of their entry into force, all relevant measures of general application which pertain to or affect the operation of this Agreement. International agreements pertaining to or affecting trade in services to which a Member is a signatory shall also be published.
2. Where publication as referred to in paragraph 1 is not practicable, such information shall be made otherwise publicly available.
3. Each Member shall promptly and at least annually inform the Council for Trade in Services of the introduction of any new, or any changes to existing, laws, regulations or administrative guidelines which significantly affect trade in services covered by its specific commitments under this Agreement.
4. Each Member shall respond promptly to all requests by any other Member for specific information on any of its measures of general application or international agreements within the meaning of paragraph 1. Each Member shall also establish one or more enquiry points to provide specific information to other Members, upon request, on all such matters as well as those subject to the notification requirement in paragraph 3. Such enquiry points shall be established within two years from the date of entry into force of the Agreement Establishing the WTO （referred to in this Agreement as the “WTO Agreement”）. Appropriate flexibility with respect to the time-limit within which such enquiry points are to be established may be agreed upon for individual developing country Members. Enquiry points need not be depositories of laws and regulations.
5. Any Member may notify to the Council for Trade in Services any measure, taken by any other Member, which it considers affects the operation of this Agreement.
三、国内规章
曾有学者一针见血地指出，“阻碍服务贸易自由化的主要障碍不是关税，而是国内的规章。”[5]这里的规章不仅包括各国对服务贸易的限制性法规和规章，还包括限制投资、资金流动等因素的国内规章。为了在尊重各国政策目标的同时推进国际服务贸易自由化进程，GATS第6条为成员方管理国际服务贸易的国内规章作出了一般规定。
Article Ⅵ
Domestic Regulation
1. In sectors where specific commitments are undertaken, each Member shall ensure that all measures of general application affecting trade in services are administered in a reasonable, objective and impartial manner.
2. （a） Each Member shall maintain or institute as soon as practicable judicial, arbitral or administrative tribunals or procedures which provide, at the request of an affected service supplier, for the prompt review of, and where justified, appropriate remedies for, administrative decisions affecting trade in services. Where such procedures are not independent of the agency entrusted with the administrative decision concerned, the Member shall ensure that the procedures in fact provide for an objective and impartial review.
（b） The provisions of subparagraph （a） shall not be construed to require a Member to institute such tribunals or procedures where this would be inconsistent with its constitutional structure or the nature of its legal system.
3. Where authorization is required for the supply of a service on which a specific commitment has been made, the competent authorities of a Member shall, within a reasonable period of time after the submission of an application considered complete under domestic laws and regulations, inform the applicant of the decision concerning the application. At the request of the applicant, the competent authorities of the Member shall provide, without undue delay, information concerning the status of the application.
4. With a view to ensuring that measures relating to qualification requirements and procedures, technical standards and licensing requirements do not constitute unnecessary barriers to trade in services, the Council for Trade in Services shall, through appropriate bodies it may establish, develop any necessary disciplines. Such disciplines shall aim to ensure that such requirements are, interalia:
（a）based on objective and transparent criteria, such as competence and the ability to supply the service;
（b）not more burdensome than necessary to ensure the quality of the service;
（c）in the case of licensing procedures, not in themselves a restriction on the supply of the service.
5. （a）In sectors in which a Member has undertaken specific commitments, pending the entry into force of disciplines developed in these sectors pursuant to paragraph 4, the Member shall not apply licensing and qualification requirements and technical standards that nullify or impair such specific commitments in a manner which:
（i）does not comply with the criteria outlined in subparagraphs 4（a）, （b） or （c）;and
（ii）could not reasonably have been expected of that Member at the time the specific commitments in those sectors were made.
（b）In determining whether a Member is in conformity with the obligation under paragraph 5（a）, account shall be taken of international standards of relevant international organizations applied by that Member.
6. In sectors where specific commitments regarding professional services are undertaken, each Member shall provide for adequate procedures to verify the competence of professionals of any other Member.
[1] Appellate Body Report on EC - Bananas Ⅲ, paras. 231-234.
[2] 石静霞：《WTO服务贸易法专论》，北京，法律出版社，2006，第63～64页。
[3] Panel Report on EC - Bananas Ⅲ, para. 7.322.
[4] Panel Report on Canada - Autos, para. 10.248.
[5] 赵维田：《世贸组织（WTO）的法律制度》，长春，吉林人民出版社，2000，第355页。