Kjøpmannskjær is a village in Færder Municipality in Vestfold county, Norway. The village is located on the southern shore of the island of Nøtterøy, about 1 kilometre (0.62 mi) east of the village of Tenvik, about 1 kilometre (0.62 mi) north of the village of Sundene (on Tjøme island), and about 3.5 kilometres (2.2 mi) south of the village of Skjerve. The village of Strengsdal lies about 2 kilometres (1.2 mi) to the east along the southern shore of the island.

The 0.46-square-kilometre (110-acre) village has a population (2023) of 440 and a population density of 953 inhabitants per square kilometre (2,470/sq mi).