The conceptions teachers have about assessment are assumed to influence their practices and to be consistent with the jurisdictional and policy frameworks in which they work. This paper compares two groups of teachers (i.e., New Zealand primary and secondary) in response to the Teachers’ Conceptions of Assessment (TCoA–IIIA) self-administered survey inventory. The previously reported four-factor hierarchical model for primary teachers (i.e., improvement, irrelevance, school accountability and student accountability) was found to be statistically invariant with good fit characteristics across both groups using nested, multigroup invariance testing in confirmatory factor analysis. The only statistically significant difference was the mean score for the student accountability conception, which was more strongly endorsed by secondary teachers, consistent with their role in administering the New Zealand qualifications system. The study suggests that teachers develop or adopt conceptions of assessment that allow them to successfully function within their own policy or legal framework.