Grennaskolan offers a large number of seasonally adapted activities within sport. Most of the sports activities are arranged by GRIFF, which is our school sports association. Membership in GRIFF is mandatory for some activities and for access to the gym. There are also sport-exchange agreements with other schools within athletics, markmanship/shooting, football, fencing, tennis, floorball, volleyball, futsal, and horse-riding. A schools championship is held annually within several team sports, such as floorball, volleyball, futsal, basketball, table-tennis and badminton.

During the last years the following sport activities have been most popular at Grennaskolan: