This study joins an intense research debate regarding whether competition is beneficial for student outcomes, focusing on the relationships between student-level and school-level competitiveness and student academic achievement. I also examine the impact of country-specific competitiveness context on the relationships between competitiveness and student achievement. This study's assumptions and hypotheses were guided by theoretical tenets of Swab & Johnson's multilevel model of competition and competitiveness and the person-culture fit model. Using Program for International Student Assessment (PISA) 2018 data and World Values Survey (WVS) data from 57 countries, I analyzed three-level hierarchical linear models (HLM) with cross-level interactions to test these hypotheses. The results showed that student competitiveness was positively related to student achievement in mathematics within schools. Between schools, a competitive climate was positively correlated to student mathematics achievement. Cross-level interactions revealed country context positively moderated the relationship between student competitiveness and achievement. These findings emphasize the importance of considering broader cultural competitiveness contexts when examining the association between student competitiveness and achievement.