This article describes an investigation that made a comparative analysis of the influence of the use of technology for non-academic activities on the reading performance of students in 21 countries within the Organisation for Economic Co-operation and Development (OECD), as measured by the Program for International Student Assessment (PISA). To do this, we coded the SumIC001-008-010 variables (”Devices available at home” and “How often do you use digital devices for the following activities outside school”) in the PISA survey and quantified the effect by the proportion of variance explained of each variable in the model for each country. The results show that the reading score increases according to the variable for type and quantity of devices at home but falls drastically in all 21 countries when the “SumIC001” variable exceeds 15 points. Our research also found that the two activities that most negatively impacted reading performance if done on a regular basis were “playing online games via social networks” and “uploading your own created contents.” These results would seem to confirm that the non-sustainability and prolonged use of technology outside school is objectively negative for the development of reading competence in young people.