The global popularity of test-based accountability appears to signal political trust in standardised assessments as valid and relevant measures of education quality. Nonetheless, research shows that educators' perceptions of standardised testing and test-based accountability can vary significantly, as do their responses to accountability demands. Considering the key influence of teachers' beliefs on the way in which they respond to education reforms, in this article we examine teachers' beliefs and opinions about standardised tests and test-based accountability. We analyse a comparative study on interpretations and experiences of standardised testing and test-based accountability demands of compulsory education teachers in Chile and Norway. These cases were selected following a most-different-systems design approach. The data was derived from an electronic survey (n = 2,531) and in-depth interviews (n = 41). The analysis shows how in both contexts, teachers are relatively critical about the validity, usefulness and fairness of standardised tests. This indicates lacking teacher trust in standardised testing and test-based accountability. Still, despite similar trends, some key differences in the beliefs of Chilean and Norwegian teachers are found, which highlight the influence of the sociocultural context in shaping teachers' beliefs. By illuminating how teachers in different contexts make sense of test-based accountability, our analysis contributes to the understanding of why the often-reported mismatch between policy expectations and policy outcomes might occur.