Three-dimensional numerical simulations of fluid flow and heat transfer in a lid-driven cavity filled with a stably stratified fluid have been performed to study the effect of a sliding lid on the flow and thermal structures in a shallow cavity. The cavity is heated from above and cooled from below. The Richardson numbers investigated are 0.1, 1, and 10 for two values of Rayleigh numbers 1 10 4 and 1 10 6 . The Prandtl number is fixed at 6.0 (water). The flow is found to be three-dimensional in nature. Interesting flow features are predicted and include longitudinal circulations for certain flow conditions.