Oncourt (French pronunciation: [ɔ̃kuʁ] ) is a former commune in the Vosges department in northeastern France. On 1 January 2016, it was merged into the new commune Capavenir-Vosges, which was renamed Thaon-les-Vosges effective 2022. Inhabitants are called Oncourtois.

The village is positioned some 3 kilometres (2 mi) to the west of the village of Thaon-les-Vosges, and crossed by the little river Avière, itself a tributary of the Moselle.

Laurent Mariotte, actor and animator with a French radio and television providers, spent a part of his childhood and adolescence at Oncourt.

• Communes of the Vosges department