The study evaluated the relationship among teaching, leadership, teacher certification, student and teacher number related factors, and index of economic, social and cultural status (ESCS), and science literacy from an international comparative perspective. 2015 dataset of the Programme for International Student Assessment for Turkey, Singapore, the United States, Korea, Italy, and Brazil was used. Two-level hierarchical linear models were established for analysis. Results revealed that school ESCS was the best predictor of science literacy across six countries and additionally teacher-related factors came to the forefront of science literacy performance. The study underlined policymakers should focus primarily on policies that increase equity in education. Furthermore, the effectiveness of investments made in factors related to leadership, teacher certification, the number of students and teachers, which contribute very little to science literacy performance, need to be more questioned. Inferences about the findings were discussed in detail, and recommendations for further research were made.