<p>Cassava is a vital global crop, but its industrial potential is limited by inherent challenges such as high viscosity, poor cold-water solubility, and the presence of toxic hydrocyanic acid (HCN). Extrusion processing is a powerful technology that overcomes these limitations through intense thermomechanical treatment. This review synthesizes current research on how extrusion modifies cassava starch, from its multi-level structure (granular, crystalline, and molecular) to its key functional properties, including gelatinization, in vitro digestibility, and rheology. The mechanisms of cyanogenic glycoside degradation are also critically examined. Key findings demonstrate that extrusion disrupts granular integrity, reduces crystallinity, and causes molecular depolymerization, which in turn leads to significant functional improvements. These include enhanced water solubility, greater paste stability with reduced retrogradation, and lower apparent viscosity. Nutritionally, extrusion offers a distinct advantage by increasing the resistant starch (RS) fraction compared to conventionally cooked starch and by effectively degrading HCN, thereby enhancing food safety. These modified properties have enabled the successful use of extruded cassava in a wide range of applications, including expanded snacks, gluten-free cereals, and instant foods. This review provides a valuable guide for optimizing extrusion processes, supporting the development of safe, high-value cassava-based foods and promoting greater sustainability within the industry.</p>