This article analyses the effect of the Berlinguer reform that was introduced in Italy in 1999 and increased compulsory schooling from eight to nine years. Hence, students had to attend school until the age of 15 instead of 14 that was required at the time and therefore to attend at least one year of upper secondary school (for pupils with a regular career). Using data from the Labour Force Surveys (1993–2010) and applying counterfactual time series and segmented regressions, we evaluate the effect of the reform on attendance and graduation rates. The results show that prolonging compulsory education encouraged a larger share of 16‐year‐olds to stay in school, especially those who were judged more at risk with less educated parents and with parents with a low occupational status. However, at age 17, part of the effect had already vanished and no effect was found on graduation rates. The compulsory schooling policy may have been more effective in adjusting the legislation to already existing student behaviour than in producing relevant changes in educational decisions.