<p>Plant proteins play a crucial role in the transition toward sustainable food systems by addressing global protein demand and environmental challenges. Despite their nutritional benefits and lower environmental footprint, plant proteins face significant barriers to consumer acceptance due to the presence of off-flavours. These undesirable sensory attributes primarily arise from some volatile and non-volatile compounds formed during protein extraction, processing, and storage. This review explores the chemical mechanisms behind off-flavour development in plant proteins and evaluates conventional and emerging mitigation techniques. Traditional approaches such as heat treatment, fermentation, and enzymatic modifications have shown varying levels of success in reducing off-flavours while preserving the functional properties of plant proteins. Recent developments in advanced oxidation processes, including ultrasound, ozone treatment, cold plasma, pulsed electric field, and ultraviolet radiation, have demonstrated promising results in off-flavour reduction by altering protein structure and degrading volatile compounds. This review highlights the potential of these innovative strategies for improving the sensory attributes of plant proteins. Each technique offers unique mechanisms for removing off-flavour compounds while influencing protein structure and functional properties, paving the way for their enhanced integration into mainstream food applications.</p>