Background: Robots have been used in the past as tools to aid the teaching of programming. There is limited evidence, however, about the effectiveness of simulated robots for this purpose. Aim: To investigate the effectiveness of a robot simulator, as a tool to support the learning of introductory programming, by undertaking empirical research involving a range of participants. Method: After the completion of a Systematic Literature Review, and exploratory research involving 33 participants, a multi-case case study was undertaken. A robot simulator was developed and it was subsequently used to run four 10-hour programming workshops. Participants included students aged 16 to 18 years old (n. 23) and trainee teachers (n. 23). Three in-service teachers (n. 3) also took part. Effectiveness was determined by considering participants’ opinions, attitudes and motivation using the simulator in addition to an analysis of the students’ programming performance. Pre- and post-questionnaires, in- and post-workshop programming exercises, interviews and observations were used to collect data. Results: Participants enjoyed learning using the simulator and believed the approach to be valuable and engaging. Whilst several factors must be taken into consideration, the programming performance of students indicates that the simulator aids learning as most completed tasks to a satisfactory standard. The majority of trainee teachers, who had learned programming beforehand, believed that the simulator offered a more effective means of introducing the subject compared to their previous experience. In-service teachers were of the opinion that a simulator offers a valuable means for supporting the teaching of programming. Conclusion: Evidence suggests that a robot simulator can offer an effective means of introducing programming concepts to novices. Recommendations and suggestions for future research are presented based on the lessons learned. It is intended that these will help to guide the development and use of robot simulators in order to teach programming.