ABSTRACT This study examines the relationships between self-regulated learning (SRL) strategies, self-efficacy (SE), and performance in STEM disciplines, including mathematics, biology, and physics. Participants included 243 high-school students from 10th-12th grades. Data were collected through self-efficacy and SRL strategies questionnaires. We used structural equation modelling (SEM) to understand the correlations between students' SE, use of SRL strategies (i.e., organization [ORG], metacognition [MC], and critical-thinking [CT]), and STEM-achievements. The findings revealed that students' SE was directly and indirectly related to students' STEM-achievements. Students' MC and CT strategies were found to mediate the link between students' SE and STEM-achievements. SE, ORG, and CT factors accounted for 47% of the variance in STEM-achievements. In addition, SE and MC factors accounted for 44% of the variance in CT. There were no-significant direct relations between ORG and MC strategies to STEM-achievements. The study's findings have practical implications for teachers, curriculum developers, and educators.