Abstarct: This quantitative ex post facto study examined differences in English language proficiency among Iraqi high school graduates from scientific, literary, and vocational majors. In Iraq, secondary education is differentiated into three academic tracks that determine students' exposure to and acquisition of English language skills. Despite the growing importance of English proficiency for higher education and employment, limited empirical research has investigated how these academic trajectories influence language competence among Iraqi students. This study aimed to test whether statistically significant differences in English language proficiency exist among graduates of the three majors and to identify which specific major groups differ from each other. A stratified random sample of 180 recent high school graduates (60 per major) was drawn from selected schools in Iraq. Data were collected using a standardized English proficiency test aligned with the Common European frxamework of Reference (CEFR) and a demographic questionnaire. A one-way analysis of variance (ANOVA) was conducted to test for global differences among the three groups, followed by Tukey Honestly Significant Difference (HSD) post hoc tests to identify specific group differences. Effect size (eta squared, η²) was calculated to determine the magnitude of observed differences. Results revealed a statistically significant difference among the three majors, F(2, 147) = 8.47, p < .001, η² = .14, indicating a large effect size. Scientific graduates scored highest (M = 74.85, SD = 7.42), followed by literary graduates (M = 68.10, SD = 6.95), and vocational graduates (M = 61.35, SD = 7.18). Post hoc comparisons showed that scientific graduates differed significantly from both literary and vocational graduates, while no significant difference emerged between literary and vocational graduates. The findings suggest that curriculum design, cognitive demands, and English exposure across academic tracks contribute to proficiency differences. Implications include differentiated instruction for teachers, track-sensitive materials for curriculum developers, and equitable resource allocation for policymakers to address proficiency gaps in non-scientific tracks.