Colloidal II-VI nanoplatelets (NPLs) are solution-processable two-dimensional (2D) quantum dots that have vast potential in high-performance optoelectronic applications, including light-emitting diodes, sensors, and lasers. Superior properties, such as ultrapure emission, giant oscillator strength transition, and directional dipoles, have been demonstrated in these NPLs, which can improve the efficiency of light-emitting diodes and lower the threshold of lasers. In this review, we present an overview of the current progress and propose perspectives on the most well-studied II-VI NPLs that are suitable for the optoelectronic applications. We emphasize that the control of the symmetrical shell growth of NPLs is critical for the practical utilization of the advantages of NPLs in these devices.