Trihexyl phosphate is primarily used as a plasticizer in the production of polymers and resins. It enhances the flexibility, durability, and workability of materials such as PVC, making them more suitable for applications like cables, flooring, and synthetic leather. Additionally, it serves as a solvent and extractant in various industrial processes, particularly in the separation and purification of rare earth metals. Its chemical stability and low volatility also make it a useful component in hydraulic fluids and lubricants, where it helps reduce friction and wear in mechanical systems. In some cases, it is employed as a flame retardant additive in materials to improve fire resistance.