This document investigates the molecular geometry and electronic transition of methylparaben (methyl 4-hydroxybenzoate) using theoretical calculations. It finds that the minimum energy conformations only differ in the location of hydrogen atoms, with the carboxylic and hydroxyl groups displaying a coplanar configuration with the benzene ring in both the ground and excited states. The most stable conformation reveals that the highest occupied and lowest unoccupied molecular orbitals contribute to the electronic transition moment and its orientation. Significant structural changes were observed between the ground and excited states.