["European Journal of Education, Volume 61, Issue 2, June 2026. ", "\nABSTRACT\nThis study examined how primary teachers' school culture, conceptualised as Academic Optimism (AO), relates to teachers' conceptions of assessment in Türkiye, where Assessment for Learning is promoted within an enduring testing culture. Using a cross‐sectional survey of 558 primary teachers, we validated measurement models for AO and Teachers' Conceptions of Assessment and then conducted latent profile analysis (LPA) on AO factor scores (collective efficacy, faculty trust, academic focus). A three‐profile solution emerged: Participatory/Effective (83.29%), Powerless/Distrustful (3.87%), and Resiliently Academic under Low Trust (12.85%). Teachers endorsed Accountability & Improvement conceptions more strongly than Irrelevance, which were modestly negatively related. BCH distal outcome comparisons showed non‐monotonic associations: Accountability & Improvement was the highest in the Resiliently Academic/Low Trust profile, whereas Irrelevance was the highest in the Participatory/Effective profile. Findings underscore heterogeneity in assessment ecologies and support profile‐sensitive approaches to assessment reform, leadership and professional learning.\n"]