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%).