Background: To build capacity among people with intellectual and developmental disabilities to become co-researchers they need the opportunity to learn about research. Method: An inclusive research team developed an online training to support people with intellectual and developmental disabilities to serve as co-researchers. Seven participants were recruited as pilot trainees. The co-researcher training consisted of two 1-h training sessions. Pre- and post-surveys and a focus group were conducted to examine participant experiences with the co-researcher training. Results: The participants were actively engaged during the co-researcher training sessions and shared they had a positive experience with it. They expressed that people with intellectual and developmental disabilities add value to the research team because of their lived experiences. Conclusion: The co-researcher training can instill a baseline level of knowledge about research in people with intellectual and developmental disabilities, and can be adjusted for different types of research in different settings and organisations.