We study the magnetotransport properties of high-mobility holes in monolayer and bilayer ${\mathrm{WSe}}_2$, which display well defined Shubnikov–de Haas (SdH) oscillations, and quantum Hall states in high magnetic fields. In both mono- and bilayer ${\mathrm{WSe}}_2$, the SdH oscillations and the quantum Hall states occur predominantly at even filling factors, evincing a twofold Landau level degeneracy. The Fourier transform analysis of the SdH oscillations in bilayer ${\mathrm{WSe}}_2$ reveals the presence of two subbands localized in the top or the bottom layer, as well as negative compressibility. From the temperature dependence of the SdH oscillations we determine a hole effective mass of $0.45m_0$ for both mono- and bilayer ${\mathrm{WSe}}_2$.