Plant proteins are being recognized as sustainable protein alternatives due to their nutritional value and environmental benefits. However, their application in the food industry is limited due to their sub-optimal techno-functional properties, such as poor solubility, emulsification, foaming, and gelling properties. To overcome these limitations, various modification techniques are being used to enhance the structural and functional properties of plant proteins. This review provides a comprehensive overview of chemical, enzymatic, physical, and emerging modification techniques, highlighting their underlying mechanism and their effects on proteins. Chemical modification techniques target specific amino acid residues to improve solubility and stability, whereas physical modification techniques alter protein structure to optimize functionality. Enzymatic approaches use enzymes such as proteases and transglutaminases to alter protein structure. In addition, novel and emerging methods such as cold plasma are promising environmentally friendly alternatives for targeted modifications. These modification techniques have a great potential to enhance the application of plant proteins in the food industry, such as in food formulations, nutraceuticals, and novel product development, including 3D-printed foods and alternative meat products. This review aims to provide insights into current advances, comparative advantages, and limitations of the modification technique and their future scope in the optimization of plant-based proteins.