This study assesses whether student exclusions from PISA 2018 in Sweden followed the criteria set by the OECD. We do this using both qualitative and quantitative methods. Our conclusion is that the exclusions made in PISA 2018 in Sweden did not follow OECD criteria and were much too high. Furthermore, interviews with school coordinators indicate that many of them misunderstood the OECD criteria. We also conclude that the National Agency for Education did not sufficiently follow up on exclusions. A review of the Swedish exclusion rate made by the OECD did not present credible results but accepted the results. A recalculation of PISA 2018 scores for Sweden where we assume non-participating students to be low performers show that results are significantly affected.