The international school market is expanding, and the number of for-profit English-medium international schools is rising.  Fueling the increase in international schools is the growing number of students seeking to enroll, many of whom are English language learners (ELLs).  Ensuring ELLs have access to the curriculum requires international school staff to be trained to work with ELLs.  The purpose of this study was to explore differences in professional development specific to working with ELLs between international schools in East Asia that are for-profit and schools that are non-profit. Additional areas examined include types of professional development, teacher efficacy, and teacher retention.  This quantitative cross-sectional survey-based study had 548 participants, 157 of whom were administrators, and 391 were teachers.  The main findings of the study revealed there are significant differences in the availability of language-specific professional development and retention rates of teachers between for-profit and non-profit international schools in East Asia.