Abstract: This mixed-methods study examined whether a robotics unit intervention with 28 sixth-grade students improved students' mathematical proportional reasoning skills and intrinsic motivation. Proportional reasoning is a difficult mathematics concept to teach. Hands-on applied robotics challenges within a constructionist/authentic learning environment helped students develop proportional reasoning skills. By using three different-sized wheels and programming the robots to travel exact distances, students learned proportional reasoning mathematic skills in real-world situations. The nonparametric Wilcoxon signed-rank test found statistically significant differences in students' change scores on two separate pre- and post-test proportional reasoning assessments, a Researcher Instrument (p = .000) and the Proportional Reasoning Diagnostic Instrument (p = .006). Scores across all categories on the Intrinsic Motivation Inventory indicated strong intrinsic motivation. The connection between robotics and real-world applications appears to have motivated students to learn. Researchers should consider robotics units as an alternative method to develop students’ proportional reasoning skills and intrinsic motivation.