Active learning and peer instruction contribute to positive learning outcomes. We developed a 25-week, question-based program for first-year medical students (MS1). Senior students developed weekly question and answer sets. Second-year peer educators helped MS1s learn to collaboratively problem solve by working through the questions and answer explanations. Controlling for average MCAT 2015 score, attendance significantly correlated with improved academic performance in basic science coursework (beta = 0.196, p < .001) and one organ systems module (beta = 0.104, p = .033). Academic outcomes and an 83% sustained participation rate point to the benefits of peer-led, positive learning environments.