This paper investigates the relationship between secondary school students’ reading metacognition and summary writing skills—which represent a part of their academic language skills—within a network of psychological and sociocultural factors consisting of positivity, tolerance and respect, resilience, and culture and cooperation. We used data from the 2018 OECD’s Programme for International Student Assessment (PISA) database (n = 612,004) from 79 countries. We conducted a series of confirmatory factor analyses (CFA) to validate the variance and covariance structure of the tests and questionnaires used. Next, we performed structural equation modeling (SEM) to investigate the effect of the predictors on reading metacognition and summary writing skills. A significant relationship was found between sociocultural factors, reading metacognition, and summary writing skills. We propose that it is essential to consider how a student’s background, experiences, and school curriculum determine how these indicators present themselves in each student and affect their academic language performance.