Multi-stack package-on-package structures are disclosed. In a method, a first stacked semiconductor device is formed on a first carrier wafer. The first stacked semiconductor device is singulated. The first stacked semiconductor device is adhered to a second carrier wafer. A second semiconductor device is attached on the first stacked semiconductor device. The second semiconductor device and the first stacked semiconductor device are encapsulated. Electrical connections are formed on and electrically coupled to the first stacked semiconductor device and the second semiconductor device.