The ankle joint orthosis immobilizes the ankle joint. The orthosis has an outer knitted part and an inner one-piece stabilizing element. The knitted part is knitted in a shape adapted to the anatomy of the area of the ankle joint and completely encloses the ankle joint. The knitted part opens in order to fit it in the position of use and then drawn together and tightened. The one-piece stabilizing element has a heel portion, a side portion which adjoins the heel portion and extends along the side of the ankle joint, and a calf portion which adjoins the side portion and engages around the rear of the calf. One or more first connector elements provided on the outside of the stabilizing element are releasably connecting to one or more second connector elements provided on the inside of the knitted part.
