Additional language learners are at risk of presenting lower language skills in the majority language compared to peers. These differences in language skills have been observed at an early stage of education and may impact academic achievement later on. A randomized trial with a switching replications design was performed in Swedish preschools to examine the effectiveness of small group dialogic reading, aiming to promote oral language skills. The sample comprised 85 children with diverse language, socioeconomic, and cultural backgrounds attending nine preschools in three school districts. Dialogic reading was conducted by ten teachers, trained in dialogic reading and coached by three special education teachers. The dialogic reading intervention was feasible in preschool context and children progressed in their oral language skills during the intervention.