2-Methyl-3-buten-2-ol (MBO232) is a biogenic volatile organic compound (BVOC), and has a large percentage of emission into the atmosphere. The vacuum ultraviolet (VUV) photochemistry of BVOCs is of great importance for atmospheric chemistry. Studies have been carried out on several BVOCs but have not extended to MBO232. In the present report, the photoionization and dissociation processes of MBO232 in the energy range of 8.0–15.0 eV have been studied by tunable VUV synchrotron radiation coupled with a time-of-flight mass spectrometer. By measuring the photoionization spectra, the adiabatic ionization energy (AIE) of MBO232 and the appearance energies (AEs) of the eight identified fragment ions (i.e., C₄H₇O⁺, C₃H₇O⁺, C₅H₉⁺, C₃H₆O⁺, CH₃CO⁺, CH₃O⁺, C₄H₅⁺, and C₃H₅⁺) were determined. High-level quantum chemistry calculations suggest that there are 3 direct channels and 5 indirect channels via transition states and intermediates accountable for these fragments. Among the reaction channels, the direct elimination of CH₃ is the most dominant channel and produces the resonance-stabilized radical cation. Most interestingly, our results show that the CH₃ selectively migrates towards the cation, which leads to the different indirect channels. The CH₃ migration is a rare process in the dissociative photoionization of metal-free organic molecules. We explain the process by molecular orbital calculations and electron localization function analysis and explore the non-conventional dissociation channels via the CH₃ roaming mechanism. We further perform kinetics analysis using RRKM theory for the channels of interest. The activation barrier, and rate constants are analyzed for the branching fractions of the products. These results provide important implications for the VUV photochemistry of BVOCs in the atmosphere.