国民待遇是国际习惯法中重要的原则，意思是外国人与当地居民有同等的待遇。根据国民待遇，如果一个国家将特定的权利、利益或特权授予自己的公民，它也必须将这些优惠给予处在该国的他国公民。在国际协定的背景下，一国必须向其他缔约国的公民提供平等的待遇，这通常指对进入当地市场的进口货品和本地生产的货品一视同仁。

虽然国民待遇的安排可对外国人有利，但同时意味着当一国剥夺了本国公民权利，可相应剥夺外国人的权利。因此，国际间出现诉求，要求制定待遇的最低标准，以提供基本的保障，以及容许进入司法进程。「国民待遇」与「待遇的最低标准」之间的冲突通常与「征收」有关，并反映了工业化和发展中国家之间的角力。许多发展中国家可征收本国公民的财产，并希望行使相同权力，征收外国人的财产。

National treatment is a principle in international law vital to many treaty regimes. It essentially means treating foreigners and locals equally. Under national treatment, if a state grants a particular right, benefit or privilege to its own citizens, it must also grant those advantages to the citizens of other states while they are in that country. In the context of international agreements, a state must provide equal treatment to those citizens of other states that are participating in the agreement. Imported and locally produced goods should be treated equally — at least after the foreign goods have entered the market.