This paper describes a 54-hour summer institute for grades 6-12 mathematics and science teachers (N = 19) with a comprehensive approach to preparing teachers to use computational thinking (CT) in their classrooms, including training in Python computer programming with Lego® Mindstorms® robotics, mathematics content sessions, and opportunities to solve real-world robotics challenges. Results of an assessment used to measure content knowledge and CT skills and the Technological Pedagogical Content Knowledge survey both yielded statistically significant increases. Participant reflections revealed they developed an enhanced understanding of programming and the ability to integrate programming into the curriculum. The authors propose an innovative approach to teaching disciplinary CT within the context of programming robots capable of interacting with the outside world to address real-world challenges.