Mjåvatn is a village in Froland municipality in Agder county, Norway. The village is located along Norwegian County Road 42, about 10 kilometres (6.2 mi) northwest of the village of Blakstad-Osedalen, about 4 kilometres (2.5 mi) south of the village of Hinnebu, and about 10 kilometres (6.2 mi) east of the village of Herefoss.