A predictive model for size and velocity distributions of droplets in a liquid spray from the disintegration of a planar sheet has been proposed, based on the maximum entropy formulation (MEF) principle. The conservation laws of mass, momentum, and energy over the breakup region serve as the constraint conditions in the MEF model. The liquid sheet breakup length, evaluated from the nonlinear stability analysis of planar liquid sheet, is used to evaluate the momentum and energy exchange terms in the conservation equations. The mass mean diameter is calculated from the breakup of cylindrical ligaments using the deformed interface profile at the time of breakup. The simulated results of the droplet size distribution are compared with the results published in the literature and reasonable agreement is observed at different conditions. The investigation has brought out the effects of gas-to-liquid velocity ratio, gas-to-liquid density ratio, and Weber number on the droplet size and velocity distributions in the liquid spray.