A chip on film package includes a base film, a chip and a heat-dissipation structure. The base film includes a first surface and a second surface opposite to the first surface. The chip is disposed on the first surface and has a chip length along a first axis of the chip and a chip width along a second axis of the chip perpendicular to the first axis. The heat-dissipation structure includes a covering portion. The covering portion at least partially covers the chip, exposes a side surface of the chip, and has a first length along the first axis and a second length along the second axis being longer than the chip width of the chip. The side surface connects a top surface and a bottom surface of the chip. A heat-dissipation structure is also provided.