Trans-3-Methylcinnamic acid is widely used in the fragrance and flavor industry due to its aromatic properties. It serves as an intermediate in the synthesis of perfumes, where it contributes to floral and sweet notes. The compound is also employed in the production of cosmetics and personal care products for its stabilizing and scent-enhancing effects, including as a UV-absorbing agent in sunscreens to protect skin from ultraviolet radiation.

In pharmaceutical research, it acts as a building block for developing biologically active molecules, including anti-inflammatory, antimicrobial, and antioxidant agents. Additionally, in biological studies, it is sometimes used as an activator or inhibitor of specific enzymes to investigate metabolic pathways in plants or animal cells.

Furthermore, it finds use in the preparation of UV-absorbing compounds for protective coatings.