Embodiments of this application provide a circuit board assembly and an electronic device. The circuit board assembly includes: a first circuit board and a second circuit board stacked with the first circuit board, where the first circuit board is provided with a first shielding frame on a surface facing toward the second circuit board, the second circuit board is provided with a second shielding frame on a surface facing toward the first circuit board, and opposite end portions of the first shielding frame and the second shielding frame are connected to a shared shielding cover, so that the shared shielding cover, the first shielding frame, and the second shielding frame enclose a shielding cavity. The circuit board assembly and the electronic device in the embodiments of this application can solve the problem that the stacked circuit boards occupy a large vertical space in the related art.