Disappointing results of international monitoring studies such as TIMSS (Third International Mathematics and Science Study) and PISA (Programme for International Student Assessment) have fuelled another general debate on the need for a sufficient level of scientific literacy and the necessity to improve the quality of science instruction in school. Science education research has played essential roles not only in analyzing the actual state of scientific literacy and the actual practice in schools but also in improving instructional practice and teacher education. A conception of science education research that is relevant for improving school practice and teacher education programs will be presented here. This conception is based on a Model of Educational Reconstruction which holds that science subject matter issues and students' learning needs and capabilities have to be given equal attention in quality development attempts. Further, research and development activities have to be intimately linked. It is argued that science education research drawing on this framework is an indispensable prerequisite for improving instructional practice and hence for the further advancement of scientific literacy.