This paper examines international criteria for assessing reading literacy, focusing on PISA, PIRLS, and related frameworks in a theoretical and methodological perspective. The study aims to justify an integrative model that connects core construct definitions, test design principles, text types, cognitive processes, and scaling procedures used to report results. The methodology combines comparative analysis, content analysis, and indicator mapping based on official assessment frameworks; it also provides a theoretical reinterpretation of task difficulty ranges and reliability evidence. The novelty lies in aligning PISA and PIRLS criteria within a unified “construct–process–text–context–psychometrics” matrix and in formulating evidence-based recommendations for adaptation to national curricula and classroom assessment. Findings suggest practical pathways for linking international large-scale assessment logic with school-level monitoring, supporting more coherent interpretation of student outcomes and instructional planning.