The paper estimates the relationship between public expenditure on secondary education and its quality. The investigation is based on regression analysis of cross-nationally comparable funding data and student performance metrics — PISA and TIMSS. The authors conclude that the growth of teachers’ salaries measured in absolute terms and public education expenditure per student have positive influence on educational achievement, though it is rather small. However, regression analysis has not revealed dependence of students’ performance on other financial indicators — public expenditure on secondary education as a percentage of GDP, public expenditure on secondary education as a percentage of total government expenditure and teachers’ salaries measured relative to average wages in the country.