Using the tight-binding approach, we investigate the energy spectrum of square, triangular, and hexagonal ${\mathrm{MoS}}_{2}$ quantum dots (QDs) in the presence of a perpendicular magnetic field. Novel edge states emerge in ${\mathrm{MoS}}_{2}$ QDs, which are distributed over the whole edge which we call ring states. The ring states are robust in the presence of spin-orbit coupling (SOC). The corresponding energy levels of the ring states oscillate as a function of the perpendicular magnetic field which are related to Aharonov-Bohm oscillations. Oscillations in the magnetic field dependence of the energy levels and the peaks in the magneto-optical spectrum emerge (disappear) as the ring states are formed (collapsed). The period and the amplitude of the oscillation decrease with the size of the ${\mathrm{MoS}}_{2}$ QDs.