Purpose: This study aims to examine the impact of an online language immersion program on the participants' self-efficacy for culturally responsive teaching. Design/methodology/approach: The Culturally Responsive Teaching Self-Efficacy Scale (Siwatu, 2007), the Culturally Responsive Teaching Outcome Expectations Scale (Siwatu, 2007) and the Culturally Responsive Classroom Management Self-Efficacy Scale (Siwatu, et al., 2015) were used to examine the impact of the intervention using a pretest/posttest analysis. Participant reflections were also qualitatively coded to provide further insight into the program. Findings: The intervention showed a statistically significant and positive change to participant's self-efficacy in the areas of culturally responsive teaching and culturally responsive classroom management. Participants showed growth in outcome expectancy, but this change was not statistically significant. Practical implications: Educators working with a high number of English learners (EL) can benefit from the intervention, which allows the educator to share in the language learning experience and gain a deeper understanding of the day-to-day challenges faced by their students. Originality/value: This study represents the second attempt to document the impact of the BaseLang Grammarless program as a professional learning intervention for K-12 educators working in schools with a high rate of EL.