We investigate the accuracy of the weighted-density approximation (WDA) in predicting the dielectric response of materials from first-principles. WDA is a genuinely non-local formulation for the exchange-correlation term of density-functional theory. Still, it can be cast into a computationally tractable scheme, allowing for practical applications in pseudopotential calculations. We have selected a group of materials with increasingly ionic character (C, GaAs, AlAs, and SrO), and we have calculated the static dielectric constant as a supercell limit of the electronic response to an applied electric field at finite q. The WDA response is found to be somewhat lower than LDA, in agreement with the experimental trend. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.