An exemplary computer enclosure includes a chassis, a pair of fixing members, a plurality of slats, and an actuating member. The chassis includes a pair of first parallel panels, and a second panel perpendicular to the first panels. The first panels and second panel cooperatively define an opening therebetween. The fixing members are attached to the first panels. The slats are pivotably attached to the first panels to adjustably shield the opening. Each of the slats includes a gear shaft fixed to an end thereof. The actuating member includes a rack bar slidably attached to one of the first panels to mesh with the gears shafts. The slats are rotatable clockwise or anticlockwise. Thus, the opening may be adjustably exposed to control an amount of air entering the chassis for dissipation of heat.