Poly(ethylene terephthalate) (PET) is a widely used polymer known for its excellent mechanical properties and chemical resistance. Due to its extensive use, it often ends up in the environment, where it fragments into micro- and nanoparticles. In these forms, it can interact with various organic contaminants, leading to significant environmental implications. Ab initio methods provide the opportunity to investigate these interactions in detail at the atomic level, enabling an understanding of the fundamental forces that govern the binding of organic molecules to the surface of PET. In this study, interactions between PET and two organic pollutants, phenol and aniline, were investigated using the DFT method M06L(GD3)/6-31G(d,p) for the geometric optimization of the interacting model systems, i.e., PET-phenol and PET-aniline in the Gaussian software package. The interaction energy was determined using the 6-31++G(d,p) basis set to better account for dispersion interactions. Furthermore, the "counterpoise" method was applied to correct for the basis set superposition error (BSSE). The resulting complexation energies for the PET-phenol and PET-aniline systems were negative, indicating favourable interactions and complex stability. However, the energy decomposition analysis revealed that the PET-aniline system exhibits stronger dispersion interactions and lower repulsion, leading to a more stable complex compared to the PET-phenol system. The electrostatic interactions were similar in both systems, with partial charges obtained from the Merz-Kollman analysis indicating significant negative charges on oxygen atoms, facilitating hydrogen bond formation. The visualization of the electrostatic potential further supported this, showing that oxygen and nitrogen atoms are key contributors to the electrostatic interactions.