This article investigates the extent to which schools can achieve both equity and quality. Data emerged from two effectiveness studies in teaching mathematics and Greek language, which were conducted to test the validity of the dynamic model of educational effectiveness. Separate multilevel analyses for each subject were conducted and it was found that the effectiveness status of schools does not change significantly when the two dimensions (equity and quality) are used to measure their effectiveness status in each subject. Changes in their effectiveness status in terms of each dimension of measuring effectiveness were also examined. In each subject, schools that were found to improve their effectiveness status in terms of the equity dimension were also found to improve their effectiveness status in terms of the quality dimension. Moreover, no school that was found to improve its effectiveness status in terms of one dimension had declining effectiveness in terms of the other dimension of effectiveness. Implications of these findings for the development of educational effectiveness research are drawn. (Contains 1 figure and 8 tables.)