The collisionless photodissociation dynamics of isobutene (i-C₄H₈) at 193 nm via photofragment translational spectroscopy are reported. Two major photodissociation channels were identified: H + C₄H₇ and CH₃ + CH₃CCH₂. Translational energy distributions indicate that both channels result from statistical decay on the ground state surface. Although the CH₃ loss channel lies 13 kcal mol⁻¹ higher in energy, the CH₃ : H branching ratio was found to be 1.7 (5), in reasonable agreement with RRKM calculations.