Using data from TIMSS 2015, this study investigated determinants of inequality between classrooms in mathematics performance in Sweden. Applying multiple-group confirmatory factor analysis and measurement invariance frameworks to identify latent constructs with which to build a two-level structural equation model, this study integrated teacher certification, teacher preparedness and school emphasis on academic success into a model of inequality of outcomes and opportunities. The study found evidence that more socioeconomically advantaged classes had better prepared mathematics teachers. School culture towards academic achievement was not associated with mathematics achievement. Finally, the analyses indicated that substantial inequalities exist for students taught by specialist and non-specialist teachers.