A concerted HCl elimination reaction is observed following ultraviolet photoexcitation of neat and matrix-isolated samples of acetyl chloride. The photoreaction of condensed-phase acetyl chloride forms HCl . ketene complexes exclusively, in sharp contrast to the gas-phase photoreaction that produces CI atoms, CH3CO, CH3, and CO. The reaction mechanism involves photoexcitation followed by S-1 --> S-0 interconversion and a four-centered elimination on the ground electronic surface. The HCl . ketene complexes are the only primary photoproduct observed and are found to be aligned with the polarization axis of the irradiating laser. The polarization specific FTIR probe indicates that the HCl ketene complexes form a T-shaped structure quite similar to the transition state structure recently calculated for HCl elimination from CH3COCl.