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 km east of the village of Tenvik, about 1 km north of the village of Sundene (on Tjøme island), and about 3.5 km south of the village of Skjerve. The village of Strengsdal lies about 2 km to the east along the southern shore of the island. The 0.46 km2 village has a population (2023) of 440 and a population density of 953 PD/km2.