Trimethyl(phenyl)tin is primarily used as a stabilizer in the production of polyvinyl chloride (PVC) plastics. It enhances the thermal stability of PVC, preventing degradation during processing and extending the material's lifespan. Additionally, it finds application as a biocide in antifouling paints, where it inhibits the growth of marine organisms on ship hulls and underwater structures. Its use in agriculture as a fungicide has also been noted, particularly for protecting crops from fungal infections. However, due to its toxicity and environmental impact, its applications are increasingly regulated and limited in many regions.