Although teacher quality is usually signalled to be the most relevant school-level factor impacting students' learning, little is known about the relevance of teacher effects explaining educational inequality. By using a value-added model for a cohort of 10th graders, in this work we examine the socioeconomic gap in teacher effects across Chilean secondary schools, and its importance in explaining socioeconomic inequality in students' achievement in math and language. We found an important proportion of highly effective teachers in low-socioeconomic-status (SES) schools, but also much bigger variation in teacher effects across those schools. Variability in teacher effects decreases when moving towards higher SES schools, where there is also a smaller proportion of low-performing teachers. All in all, teacher effects have a levelling impact for students in low-SES schools when compared to those in middle SES schools, but no significant impact when compared to students in high-SES schools.