Microdisk lasers are important components in photonic integrated circuits (PICs), of which the whispering gallery modes (WGMs) are usually confined within a two-dimensional (2D) planar slab. Here, owing to the strain relaxation of quantum wells by wet-etching method, we present ultra-thin curved visible microdisk lasers with single-mode lasing emission and a high quality factor of ∼17,000, which enable a 3D spatial intensity distribution of WGMs and provide an extra degree of freedom for the confined photons compared with the conventional 2D inplane WGMs. The curved microdisk lasers with a 3D spatial profile of WGMs may provide attractive applications in flexible and multilevel photon sources for the PICs.