The present study examines two factors in relation to English L3 proficiency development and school performance in a third language: (a) parental education and (b) second language exposure within the living community. Participants (n?=?50) are Italian L1 students with German L2 and English L3. All students (eighth grade, 14 years of age) were attending school in the multilingual region of South Tyrol, Italy, in 2005/2006. Final year written exams were examined in relation to parental education and the language most frequently spoken in the community (Italian L1 or German L2) with the aim to identify which of the two factors (parental education or L2 exposure) best predicts school performance and English L3 proficiency development. Overall results show parental education to be a stronger predictor of English L3 development.