Hydroxybenzenes (HYBs) are interesting both for their own properties and because some of them are parent compounds of large classes of compounds, including flavonoids, resorcinolic lipids and phloroglucinols—many of which exhibit a variety of biological activities (antibacterial, anticancer, antioxidant, antiparasitic, and others). The presence of OH groups enables the formation of O–H⋯O hydrogen bonds between two HYB molecules, and the possibility of stacking interactions between the two aromatic rings may significantly influence the geometry of the resulting dimer. Dimers of all the HYBs were calculated, considering inputs with all the possible mutual geometries’ and bonding arrangements for the two units. Four sets of calculations were performed at the DFT level, utilising the B3LYP and the M06-2X functionals with the same 6−31+G(d,p) basis set; for each functional, calculations were performed without and with the Grimme’s dispersion correction. The results highlight the importance of the consideration of dispersion effects on the estimation of the dimers’ properties. The geometrical and bonding preferences of the dimers depend on the number and positions of the OH groups in the HYB molecules. The competition between intramolecular and intermonomer hydrogen bonds for HYBs containing consecutive OH groups is also analysed.