The Aavoja is a 22.1 km (13.7 mi) long river in Anija Parish, Harju County, Estonia that flows into the Jägala River near Kehra.

The current source is located in the village of Pillapalu, just south of Koitjärve Bog.

The upstream part of the river was dug in the 1930s to drain Aguparra Bog.

The river is part of the Tallinn water supply system.

This article related to a river in Estonia is a stub.