This quantitative study examines the second language (L2) oral comprehensibility of 30English immersion learners, 15 girls and 15 boys, at an international school in South America (ISSA). At the end of 12th grade, these predominantly first language (L1) Spanish speakers gave speeches in English to a school audience. These speeches were recorded, and two audio extracts per student were selected. Native speakers of English listened to theses amples and rated them based on their own perceptions of each student‘s oral comprehensibility, i.e., ease of understanding (Derwing& Munro, 2005; Munro & Derwing, 2015). Female students received significantly higher comprehensibility scores than did male students. Students who had transferred to ISSA from other schools also tended to receive higher comprehensibility scores than those who had been schoole dat ISSA since kindergarten. The current study extends the field of comprehensibility research to the population of immersion learner sand to the curriculum component of school speeches as well as to the relationship between rater-perceived L2 comprehensibility and each student‘s gender and schooling. This study has direct implications for L2 instruction, assessment, and research.