Abildsø is a residential area in the borough of Østensjø in Oslo, Norway. It is located southeast of the city center. Abildsø is largely characterized by single-family homes and green spaces. The area is bordered by the Østensjøvannet lake to the west and the E6 highway to the east.
Historically, Abildsø was a farming area, and remnants of this agricultural past can still be seen in some areas. Today, it is primarily a residential neighborhood with schools, kindergartens, and local shops.
The name "Abildsø" is derived from the Old Norse words "apaldr" (apple tree) and "sœr" (lake), meaning "apple tree lake".