An embodiment is a package including a first package component. The first package component including a first die attached to a first side of a first interconnect structure, a molding material surrounding the first die, and a second interconnect structure over the molding material and the first die, a first side of the second interconnect structure coupled to the first die with first electrical connectors. The first package component further includes a plurality of through molding vias (TMVs) extending through the molding material, the plurality of TMVs coupling the first interconnect structure to the second interconnect structure, and a second die attached to a second side of the second interconnect structure with second electrical connectors, the second side of the second interconnect structure being opposite the first side of the second interconnect structure.