We analyse the impact of a One Laptop per Child program introduced by the Catalan government on student achievement. Using longitudinal population data for students in secondary education during the period 2009–2016, our identification strategy exploits variations across cohorts within schools. Although participation into the program was not random, we control for a number of school characteristics that influenced school participation. The empirical results consistently indicate that this program had a negative impact on student performance in Catalan, Spanish, English and mathematics. Test scores fell by 0.20–0.22 standardised points, which represent 3.8–6.2% of the average test score. This negative effect was stronger among boys than it was among girls (differences ranging from 10% to 42%).