The most critical requirement of an online class is the availability of the internet for a teacher and students alike. The objective of this study was to find out how student internet access correlates to teachers’ self-efficacy in teaching an online class. This quantitative study used categorical data obtained using two questionnaires, one of which was student internet access consisting of three constructs, and the other is teachers’ self-efficacy in teaching an online class. The questionnaires were distributed online to in-service teachers who had completed or almost completed an online teacher professional development program in four major universities in Indonesia. As many as 158 teachers completed both questionnaires. The data were analyzed using Spearman Correlation Coefficient to reject the null hypothesis at the significance level of 0.05. The correlation was calculated for seven teacher categories, i.e. teachers in urban areas, teachers in rural areas, elementary school teachers, junior high school teachers, senior high school teachers, experienced teachers, and inexperienced teachers. The research results show that teacher-reported student internet access correlates with teachers’ self-efficacy in teaching an online class. The level of correlation ranges from weak to strong correlations, with moderate correlations for most teacher categories. The implication of this study for teacher education is also discussed.