Kjeller Flyfabrikk (Kjeller Aircraft Factory) a contraction of Kjeller Flyvemaskinsfabrik (Kjeller Flying machine factory), was a Norwegian manufacturer of military aircraft. It was formally established in 1915, but was active from 1912. The factory was owned by the Norwegian government under the management of the Norwegian Army Air Service and was also known as the Hærens Flyfabrikk.

It mainly built foreign types of aircraft under license, but also developed several types.