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We report the observation of a reentrant insulator-metal-insulator transition at B= 0 in a two-dimensional (2D) hole gas in GaAs at temperatures down to 30 mK. At the lowest carrier densities the holes are strongly localized. As the carrier density is increased a metallic phase forms, with a clear transition at σ≃ 5 e 2/h. Further increasing the density weakens the metallic behavior and eventually leads to the formation of a second insulating state for σ≳ 5 0 e 2/h. In the limit of high carrier densities, where k F l is large and r s is small, we thus recover the results of previous work on weakly interacting systems showing the absence of a 2D metallic state.