Model-driven approaches to software engineering have expanded their influence in recent years, with Object Management Group's model-driven architecture (MDA) being the major force behind this boost. However, despite its merits, MDA remains insufficient for software system development, in the sense that it does not provide a concrete and comprehensive process for governing software development activities. There is therefore a strongly felt need for new model-driven software development methodologies. In this paper we review a number of existing model-driven methodologies, and propose a general framework for model-driven development (MDD) based on MDA. The framework can be used for assessing and comparing methodologies, engineering new methodologies, and adapting existing ones so that they meet the special requirements of the model-driven approach. We have used the framework herein to show how agile methodologies fare in this model-driven development context.