Background <p>International large-scale assessments such as TIMSS offer valuable insights into teaching effectiveness. However, student-reported measures often exhibit perceptual variability, raising concerns about their reliability and validity.</p> Methods <p>This study applies a climate strength model to assess not only the average level of teaching quality but also instructional climate strength, operationalised as within-classroom dispersion in student perceptions. Using TIMSS 2023 data from participating educational systems, this study examines two key dimensions of teaching quality, instructional clarity and classroom management, in both mathematics and science, with analytic samples varying by subject and measure availability.</p> Results <p>Multilevel modelling reveals that higher classroom-average teaching quality is associated with better student achievement. Crucially, stronger instructional climate strength further is associated with learning outcomes in some educational systems. In a few educational systems, inconsistent student perceptions appear to diminish the benefits of high-quality teaching, supporting the instructional climate strength hypothesis. Nonetheless, cross-national differences indicate that cultural and pedagogical contexts shape these patterns.</p> Conclusions <p>This study advances methodological approaches for evaluating teaching quality in large-scale assessments, highlighting the importance of considering both the level and consistency of instructional climate. The findings carry important implications for education policy, teacher training, and assessment design, encouraging strategies that promote not only effective but also equitably experienced teaching quality.</p>