Quadrupel is a type of strong ale, brewed in the Belgian style. Brands of quadrupels include La Trappe Quadrupel brewed by De Koningshoeven Brewery in the Netherlands, and Saint Louis Brewery's seasonal Schlafly Quadrupel Ale.

In other countries, particularly the United States, 'quadrupel' or 'quad' may refer to an especially strong style of dark ale, with a characteristic spicy, ripe fruit flavor.

A quadrupel is intended to be stronger than a Tripel, so the ABV strength will be 10 % or more. Beyond that, there is little agreement on the status of quadrupel as a style.