The parish of Haa was established as a municipality on 1 January 1838 (see formannskapsdistrikt). It was divided into Nærbø and Varhaug in 1894. The municipality of Hå was (re)created after the merger of Nærbø, Varhaug, and Ogna on 1 January 1964. In local politics, the divisions between the three previous municipalities are very visible.
The coat-of-arms is from modern times. They were granted on 5 July 1991. The arms show a special type of local winch, used to remove stones from the fields. It also symbolizes the hard living on the rocky soils of the municipality.