Two new ground state potential energy surfaces have been obtained for the ArCl₂ Van der Waals complex, one purely ab initio, the other constructed from empirical ArCl potentials modified in terms of ab initio data for the ArCl₂ and ArCl moieties. The ab initio surface has a well for the linear conformer that is slightly deeper than that for the T-shaped conformer, but inclusion of the zero-point energies reverses the relative binding in the two configurations. The microwave spectrum has been calculated using the new potential surfaces, and a series of lines that can be associated with the linear conformer have been predicted. Possible reasons for their nonobservability under the usual experimental conditions are discussed. A simple modification which employs empirical information on the ArCl potentials used in modelling the ArCl₂ potential surface transforms the well for the T-shaped conformer into the global minimum, with a dissociation energy that lies within 0.5% of the experimental value, and microwave transition energies that deviate from experimental values by no more than 1.3%. A final 2-parameter scaling allows reproduction of both the experimental D₀ value (within experimental uncertainty) and the positions of all observed microwave lines (within 0.02%) for each of the ab initio and empirically-based potential surfaces.