Achtkarspelen (Dutch pronunciation: [ɑxtˈkɑrspələ(n)] ⓘ) is a municipality in the province of Friesland in the Northern Netherlands.

The name Achtkarspelen, literally meaning "eight parishes", is derived from the original eight parishes within the grietenij, namely: Augustinusga, Buitenpost (the capital), Drogeham, De Kooten, Kortwoude, Lutkepost, Surhuizum and Twijzel.

Achtkarspelen held a separate status within Friesland for many years.

In the Middle Ages Achtkarspelen fell under the Bishopric of Münster, meanwhile the rest of Friesland was a part of the Bishopric of Utrecht.

The grietenij Achtkarspelen became a municipality in 1851 as a result of the Municipality Act of Minister of the Interior Johan Rudolph Thorbecke.