In the past decade, metal-halide perovskites have attracted increasing attention in optoelectronics, due to their superior optoelectronic properties. However, inherent instabilities of conventional three-dimensional (3D) perovskites over moisture, heat, and light remain a severe challenge before the realization of commercial application of metal-halide perovskites. Interestingly, when the dimensions of metal-halide perovskites are reduced to two dimensions (2D), many of the novel properties will arise, such as enlarged bandgap, high photoluminescence quantum yield, and large exciton binding energy. As a result, 2D metal-halide perovskite-based optoelectronic devices display excellent performance, particularly as ambient stable solar cells with excellent power conversion efficiency (PCE), high-performance light-emitting diodes (LEDs) with sharp emission peak, and high-sensitive photodetectors. In this review, we first introduce the synthesis, structure, and physical properties of 2D perovskites. Then, the 2D perovskite-based solar cells, LEDs, and photodetectors are discussed. Finally, a brief overview of the opportunities and challenges for 2D perovskite optoelectronics is presented.