The kinetics of the thermal unimolecular decomposition of the cyclohexoxy radical (c-C₆H₁₁O) was experimentally studied, and the results were analyzed in terms of statistical rate theory with molecular and transition state data from quantum chemical calculations. Laser flash photolysis of cyclohexylnitrite at 351 nm was used to produce c-C₆H₁₁O radicals, and their concentration was monitored by laser-induced fluorescence after excitation at 356.2 or 365.2 nm. The experiments were performed at temperatures ranging from 293 to 341 K and pressures between 5 and 55 bar with helium as the bath gas. Over the whole temperature range, biexponential profiles were observed, which is an indication of a consecutive reaction with a pre-equilibrium. From our quantum chemical calculations, it follows that this pre-equilibrium corresponds to the reversible ring-opening via β-C–C bond fission to form the 6-oxo-1-hexyl radical (l-C₆H₁₁O), c-C₆H₁₁O ⇔ l-C₆H₁₁O (1,–1). The following temperature-dependent rate coefficients were deduced with an estimated uncertainty of ±30%: k₁(T) = 3.80 × 10¹³ exp(–50.1 kJ mol^–1/RT) s^–1 and k_–1(T) = 3.02 × 10⁸ exp(–23.8 kJ mol^–1/RT) s^–1; a pressure dependence was not observed. In our theoretical analysis, the different conformers of c-C₆H₁₁O were explicitly taken into account, and the C–C torsional motions in l-C₆H₁₁O were treated as hindered internal rotators using a recently suggested approach. This explicit consideration of the hindered internal rotators significantly improved the agreement between the experimentally determined rate coefficients and the results from the quantum chemical computations.