This work reports the interaction of γ-rays with MoO3 in several solvents to obtain non-stoichiometric (sub-oxide) MoO3-x through a one-pot synthesis. The effect of different doses of γ-radiation (30-90 kGy) with different protic solvents (water, N,N-dimethylformamide and formic acid) was investigated. Structural modifications were characterized by X-ray diffractometry and scanning electron microscopy while optical properties were investigated by UV-Vis spectroscopy. The analysis of the highly intense (020), (040) and (060) diffraction peaks suggests that there is a reduction in water and formic acid allowing the formation of MoO3-x nanosheets. Additionally, the photothermal response of MoO3-x obtained under different conditions was characterized, and a possible mechanism to explain the interaction of γ-rays with solvents and the oxide structure by oxidative/reductive processes in the solution was proposed.