He has been active in international educational research over a period of more than 20 years with research interests that focus on the learning and teaching of science as a process of inquiry and the use of educational technologies as a tool for promoting critical evidence-based thinking. The Learning in Science Group uses the results of this research in the development of online learning environments, such as the STOCHASMOS platform, and research-based teaching-learning sequences to promote conceptual understanding and scientific thinking. Dr Constantinou has co-ordinated a number of projects funded by the European Commission and the Cyprus Research Promotion Foundation. He has participated in the High Level Expert Groups that authored the reports Science Education for Responsible Citizenship in 2015 and Europe needs more Scientists! in 2004; he was the Rapporteur in a group of experts that carried out the mid-term evaluation of the EC Science in Society program in FP6 and he has participated in an expert panel on the educational outreach programme of the European Space Agency. He is currently President of the European Science Education Research Association (ESERA).