We examined the effects of deliberate practice (DP) in teaching motivational interviewing (MI) helping skills to 45 upper-level undergraduate students in a semester-long course using an experimental crossover waitlist design. Students participated in a three-hour MI skills workshop focused on open-ended questions, affirmations, reflections, and summaries (OARS) and engaged in ongoing practice throughout the semester. Students video-recorded four skill demonstrations involving real-life changes with a volunteer client, addressing behavioral change. Pre- and post-workshop video recordings were analyzed to evaluate changes in reflective listening skills and the overall consistency of using MI OARS skills. The results revealed significant increases in reflections-to-questions ratio, consistency in using MI OARS skills, and decreased use of statements that were inconsistent with MI. Additionally, students reported increased learning and self-efficacy in using MI skills. These findings suggest that integrating DP into undergraduate courses enhances the frequency and proficiency of MI-helping skills among undergraduate students preparing for the helping professions. The practical implications extend to preparing students for graduate programs or careers in the helping professions. Public Significance: This study highlights the potential benefits of incorporating DP with MI in undergraduate courses. By using experiential methods to introduce students to MI and its principles, this approach may lay the foundation for developing greater confidence and a solid foundation for building advanced helping skills as novices prepare to enter graduate programs in the helping professions.