This application provides a speaker and a mobile terminal. The speaker includes a housing and a kernel located in the housing, where there is a front cavity and a rear cavity in the housing, the front cavity is in communication with the outside, and the rear cavity is an isolated cavity. In addition, to reduce a space area occupied by the entire speaker, the front cavity and the rear cavity are disposed in a stacked manner when being disposed. Specifically, the front cavity and the rear cavity are at least partially stacked along a thickness direction of the kernel. Therefore, the rear cavity is disposed in space of the entire speaker in the thickness direction of the kernel, to reduce an area occupied by the entire speaker in the mobile terminal on the premise that a size of the rear cavity meets a requirement.