Glutathione transferase-P1-1 (hGSTP1-1), which is associated with acquired drug resistance in some tumour cells, requires two identical subunits for full activity. Naturally occurring inhibitors for GSTP1-1 quaternary structure could be interesting therapeutic agents. The aim of this study was to investigate potential binding sites for hGSTP1-1 interaction with ligands many of which occur naturally. Simulations were performed with commercial docking software and with GST monomer or dimer as template. Docking results using hGSTP1-1 dimer showed one binding site for most of the ligands tested. Lycopene, glutathione, ellagic acid, ethacrynic acid, quercetin, caffeic acid, ferulic acid, porphyrin, curcumin, cinnamic acid, and also α-tocopherol bound at the enzyme dimer subunit-subunit interface. In contrast, investigations using hGSTP1-1 monomer revealed three additional sites for ligand binding. In conclusion, the docking simulations suggest that the enzyme subunit interface may be important for hGSTP1-1 interactions with ligands. These findings may provide valuable insights for further research to identify naturally occurring therapeutic agents.