III-V active devices and their efficient coupling and integration with passive components are crucial for the further development of silicon photonics. Heteroepitaxy for integrating efficient III-V lasers on silicon can enable wafer-scale silicon photonic-integrated circuits, maximizing the benefits of silicon photonics at low cost, high throughput, large bandwidth, and large-scale integration. This article examines III-V active devices on silicon-on-insulator (SOI) via lateral selective epitaxy, focusing on the integration of III-V lasers and photodetectors on SOIs and their efficient in-plane coupling with silicon-based passive components. This article discusses their unique characteristics, including bufferless, in-plane configurations and laterally stacked active regions, as well as their future development prospects.