Chapter 2 covers the period from 1960 to 1980 and analyses how teachers’ unions emerged as the most powerful force in education policy, often at the expense of other interest groups – most notably the private school associations and parental groups. The chapter investigates how this shift in influence shaped major education reforms of that era. It explains how governments found it relatively easy to expand secondary education to an entirely new generation, as teachers’ unions stood to gain substantial material benefits. In contrast, governments faced extraordinary difficulties in integrating the selective education systems into comprehensive school types aimed at promoting social inclusion, largely due to strong union opposition. Additionally, the chapter analyses how teachers’ unions, in fierce competition with other interest groups, consolidated and extended their influence at local levels across the case countries and the European Union.