The aim of my study was: (a) to measure the effectiveness of a supporting tutor-training curriculum and content knowledge gains for preservice teachers engaged in service learning and (b) to determine whether tutor training and field experience improved the preservice teachers' teaching self-efficacy beliefs. One hundred and thirteen upper-division undergraduate students enrolled in Social Foundations of Multicultural Education courses participated in course-embedded tutor-training and fulfilled a 20-h service-learning requirement by tutoring pupils in local elementary schools. Analyses of variance (ANOVA) on a pretest and posttest measures of content knowledge, tutoring skills, and teaching self-efficacy demonstrated a statistically significant difference with higher mean scores at the post time. These results suggest that a course-specific tutor-training curriculum advances the participants' knowledge and skill in tutoring. The results also indicate that the combination of tutor training and field application (i.e. tutoring in a classroom) function to increase students' self-efficacy as future teachers.