国民待遇，national treatment，是指国家在一定范围内给予外国人与本国公民相同的待遇。根据国际实践，国家给予外国人国民待遇，一般限于民事权利和诉讼权利。政治权利排除在外。国民待遇通常是国家间在互惠原则的基础上互相给予的。

差别待遇，differential treatment，指国家给予外国人不同于本国公民的待遇，它包括两种情况：

国家给予外国公民或法人的民事权利，在某些方面少于本国公民或法人；

对不同国籍的外国公民和法人给予不同的待遇。

最惠国待遇，most-favored-nation treatment，是指一国给予另一国的国民或法人的待遇，不低于现时或将来给予任何第三国国民或法人在该国享受的待遇。最惠国待遇一般是通过条约中的最惠国条款给予，通常适用于经济和贸易方面。

参考双语例句：

It was suggested that this guarantee should be viewed as a matter of national treatment: insofar as mechanisms for legal aid existed in the expelling State, an alien must have access to them on a non-discriminatory basis.

有人建议，这项保证应被视为国民待遇事项：就驱逐国的法律援助机制来说，外国人必须在不受歧视的基础上予以使用。

Special and differential treatment must remain an integral part of the multilateral trading system in order to enable developing countries, in particular the most economically vulnerable, to fulfil their commitments and facilitate their integration in world trade.

仍须把特殊和差别待遇列为多边贸易体制的一个组成部分，以便使得发展中国家，尤其是经济上处于最弱势地位的国家能够履行其承诺，并方便其融入世界贸易。

National treatment and most favoured nation treatment, the core principles of the multilateral trading system, had much in common with human rights issues concerning individual freedom, non-discrimination, equal opportunities and respect for the rule of law.

国民待遇和最惠国待遇是多边贸易体制的的核心原则,与关于个人自由、不歧视、机会平等和尊重法治的人权问题有许多共同之处。

UNCTAD also prepared two revised issues of the first generation series on Key Issues in IIAs: “Scope and Definition revisited” and “Most-favored-nation treatment revisited”, and advanced the preparations of “Fair and equitable treatment revisited”and “Expropriation revisited”.

 贸发会议还就国际投资协定关键问题编写了第一代系列的两个文件修订稿：“范围和定义再评”和“最惠国待遇再评”，并在编写“公平公正待遇再评”和“征用再评”方面取得了进展。