The COVID-19 pandemic significantly impacted the mental health of adults with intellectual and developmental disabilities (IDD). During this period of uncertainty and need for up-to-date information, various virtual training programmes demonstrated the role of tele-mentoring programmes. The aim of this paper is to describe the educational evaluation of the National Extension for Community Healthcare Outcomes - Adults with Intellectual and Developmental Disabilities (ECHO-AIDD), a programme for service providers working with adults with IDD during COVID-19. The programme consisted of six sessions, conducted weekly, over two cycles. Each session included didactic teaching by hub team members, COVID-19 news updates, wellness check-ins and a brief mindfulness activity, followed by a 30 to 45 min case-based discussion. The hub structure had an inter-professional approach to team expertise. Those with lived experience were an integral part of the content experts' hub. Pre-, post- and follow-up evaluation data were collected. Care providers from health and social care sectors (n = 230) participated in the programme. High levels of engagement and satisfaction were reported. Self-efficacy ratings improved from pre- to post-, and were maintained at 8-week follow-up; improvement from pre- to post- was significant (P < 0.0001). Exposure to National ECHO-AIDD educational intervention led to improvement in perceived competencies. This study also shows the valuable role of people with lived experience in fostering adaptive expertise in learners. The outreach and scalability support the feasibility of building a national virtual community of practice for IDD service providers. Future studies should focus on studying the impact of these programmes on the health outcomes of people with IDD.