Production of distilled water from a single slope solar still, which is equipped with external reflectors of four sides, has been investigated for typical summer and winter conditions using experimental and numerical techniques. Mass and heat transfer inside the solar still have been considered in modelling the distillation process. Numerical results have been validated with the experimental measurements. It was found that using external reflectors can increase the distilled water production significantly. The enhancement of the production by using the external reflectors is measured to be 40% in the summer and 85% in the winter as compared with the solar still without the reflectors.