A package structure includes a redistribution structure, a chip, one or more structural reinforcing elements, and a protective layer. The redistribution structure includes a first circuit layer and a second circuit layer disposed over the first circuit layer. The first circuit layer is electrically connected to the second circuit layer. The chip is disposed over the redistribution structure and electrically connected to the second circuit layer. The one or more structural reinforcing elements are disposed over the redistribution structure. The structural reinforcing element has a Young's modulus in a range of 30 to 200 GPa. The protective layer overlays the chip and a sidewall of the structural reinforcing element.