This study investigates inter-school variations in several dimensions of opportunity to learn as well as examines the extent to which these measures significantly affect students' performance on grade 7 literacy and numeracy exams. After situating the study within the global discourse emphasizing the importance of providing access to quality education to all children and youth, the article reviews the theoretical and empirical literature on opportunity to learn. Data for this study come from the Annual School Census, national examination results, and a field study conducted in 2011 in 190 schools in all 9 provinces in Zambia. The findings indicate variation across schools in measures of opportunity to learn: a) days schools was open during year, b) hours schools was open during the day, c) teacher absenteeism, d) teacher late arrival/early departure, e) student absenteeism, and f) student late arrival/early departure. The regression analysis findings indicate that, of these dimensions of opportunity to learn, only student late arrival/early departure had significant and relatively large effects on both literacy and numeracy exam performance, when controlling for other sets of variables in the models (teacher quality, inservice education and supervisory support of teachers, and school/community context). The article concludes by considering why the findings do not strongly support the theory of opportunity to learn.