Worldwide, the interest of policy-makers in participating in studies from the International Association for the Evaluation of Educational Achievement (IEA), such as Trends in International Mathematics and Science Study (TIMSS) has been growing rapidly over the past two decades. These studies offer the opportunity to relate the teaching and learning context to student achievement. This article presents the results of a systematic review of the research literature on TIMSS. Its main purpose is to find out to what extent TIMSS has contributed to insights into "what works in education and what does not", particularly with regard to school and classroom factors. The review was guided by a generic framework developed within the tradition of educational effectiveness research. The review showed that: (a) since 2000, the number of publications which use TIMSS data for secondary analyses aimed at explaining differences in student achievement has increased strongly; (b) a number of studies, especially older ones, did not take account of the specific sample and test design of TIMSS; and (c) there are large differences between countries in school and classroom factors associated with student achievement. In the light of these results, we discuss the benefits and limitations of country and system comparisons. (Contains 5 tables, 1 figure, and 2 notes.)