A thermal dissipation holder for a handheld electronic device is provided. The thermal dissipation holder includes a main structure, a movable element, an elastic element, and a locker. The main structure has a front surface and a rear surface. The movable element is movably connected to the main structure along a first direction and has a clamp portion at a side away from the carrier. One end of the elastic element is connected to the main structure. The other end of the elastic element is connected to the movable element. The elastic element drives the movable element to move along the first direction. The locker is disposed in the main structure and has a locking portion, where a position of the locking portion corresponds to that of the clamp portion, and the locker is selectively engaged with the clamp portion through the locking portion to lock the movable element.