<p>Transistor-type optoelectronic sensors (OESs), which integrate transistor architectures with photodetection, have become an important platform for advancing optoelectronic sensing technologies. Their electrical tunability and structural versatility enable programmable mapping between optical inputs and electrical outputs, extending sensing capabilities beyond those of conventional two-terminal devices. These attributes position transistor-type OESs as promising candidates for in-sensor signal encoding and computing. Recent developments have shown a clear evolution from basic light intensity detection towards multifunctional perception, with advantages in edge extraction, machine vision and high-dimensional photodetection. This Review surveys the operating principles, device architectures and gate-tunable photoresponses that underpin this class of sensors. Progress at the interface of bioinspired design and intelligent algorithms is highlighted, illustrating how transistor-type OESs are being shaped into platforms that are capable of complex, adaptive functionality. The key challenges and opportunities that may guide the future development of transistor-type OESs are then outlined.</p>