This article argues that trade embargoes toward illegal settlements in occupied territories are an obligation under general public international law, when such trade primarily benefits the occupant. In this case, the self-executing duty of non-recognition applies. There is no need for an explicit trade embargo imposed by the United Nations Security Council. For, transferring parts of an occupant's civilian population to occupied territories, and gaining economic benefits from occupation, both violate peremptory norms of public international law. Equally, withholding trade is also permitted under the law of the World Trade Organization (WTO). This article shows that according to Article XXVI.5.(a) of the General Agreement on Tariffs and Trade (GATT), the GATT does not apply to illegal settlements. A WTO panel could reach this conclusion, either by denying jurisdiction through finding that the occupying State has no legal standing or by scrutinizing Article XXVI.5.(a) on its merits. However, if a panel would, erroneously, decide the GATT does apply to settlements ; trade sanctions could still be allowed in a dispute settlement. This can be done by either accepting the relevant rules of public international law as an independent defense, or by using it in the interpretation of public moral and security exceptions under GATT Article XX and XXI.