Linking country-level educational achievement with other country-level indicators has the potential to drive systemic educational changes, as these correlates may reflect characteristics relevant for policy-making decisions to improve educational effectiveness. This study establishes a nomological network of educational achievement at the country level, with clusters of country variables derived from psychological, sociological, and other country-comparative research. Country educational achievements were compiled from all cycles of the Programme for International Student Achievement (PISA), and the Trends in International Mathematics and Science Study (TIMSS) for Grade 8 and Grade 4 students. These scores were found to be correlated with (a) affluence and educational investment indicators (positive); (b) intelligence (positive); (c) religious diversity (positive); (d) values pertaining to long-term orientation (positive), autonomy (positive), uncertainty avoidance (negative), and embeddedness (negative); and (e) aggregated scores of conscientiousness, openness, self-esteem, and teacher self-reports of job satisfaction and efficacy (negative). Policy implications are discussed.