Forest Abbey (French: Abbaye de Forest) or Vorst Abbey (Dutch: Abdij van Vorst) was a Benedictine abbey located in the Brussels municipality of Forest, Belgium.

It was founded in 1105 and existed for nearly 700 years, until its partial destruction by fire in 1764.

The abbots of Affligem Abbey, which had been the ecclesiastical owners of the parish since the Bishop of Cambrai ceded it to them in 1105, decided to build a priory for women in Forest, which would eventually become Forest Abbey.

Also in the 13th century, the Romanesque Church of St. Denis was rebuilt in the newer Gothic style.

The buildings that survived the dismantling are now owned by the Brussels municipality of Forest, and are used as a cultural centre for seminars, banquets and exhibitions.