The changes that have occurred in accepted approaches to teaching and learning in recent years have been underpinned by shifts in psychological and pedagogical theory, culminating in moves towards a constructivist view of learning. This paper looks at the consequences of these theoretical shifts for Computer Assisted Learning (CAL). Moshman has identified three interpretations of constructivism: endogenous constructivism which emphasises learner exploration, exogenous constructivism which recognises the role of direct instruction, but with an emphasis on learners actively constructing their own knowledge representations and dialectical constructivism which emphasises the role of interaction between learners, their peers and teachers. This classification scheme provides a framework for looking at the various constructivist approaches to CAL. For example, constructivist CAL materials that draw on the endogenous view include hypermedia environments, simulations and microworlds. Materials that draw on the exogenous view include learner controlled tutorials, cognitive tools and practice modules. Lastly, materials that draw on the dialectical view include Computer Supported Collaborative Learning (CSCL) tools and support (or scaffolding) tools.