A magnetic building block and a magnetic building block toy are provided, and belong to the technical field of building block toys. The magnetic building block toy includes at least one group of magnetic building blocks. Each group of magnetic building blocks include a first building block and a second building block. A first sensor of the first building block is configured to: sense, when the first building block and the second building block approach each other, a magnetic signal generated by a second magnet of the second building block and output a first trigger signal, to cause a first circuit board to control a first light-emitting module of the first building block emit light. The magnetic building block toy in the present disclosure has better sealing property, assembling efficiency, production efficiency, playability, service life, the like.