The title compound was prepared by base hydrolysis of (p‐MeOC6H4)2SeCl2 in water and isolated as the crystalline monohydrate, (p‐MeOC6H4)2SeO·H2O, in which the water molecule is associated via hydrogen‐bonding. Water‐free (p‐MeOC6H4)2SeO was obtained crystalline after drying and recrystallisation from toluene. Both crystal phases were investigated by single crystal X‐ray diffraction. Preliminary DFT calculations at the B3LYP/LANL2DZdp level of theory suggest that the hydrogen bonded complexes R2SeO·H2O (R = H, Me, Ph) are by 2.79, 3.36 and 11.10 kcal mol−1 more stable than the corresponding elusive diorganoselenium dihydroxides R2Se(OH)2. The hydrogen bond energies of R2SeO·H2O (R = H, Me, Ph) are 5.98, 7.18 and 5.89 kcal mol−1.