Background: Little is known about the experience of growing up with a mother with intellectual disability. The aim of this study was to explore this experience from the perspective of adult children. Method: In-depth interviews with 23 adult children brought up by mothers with moderate-to-severe intellectual disability. The interview data were analysed using grounded theory methods. Results: The childhood experiences of the interviewees and the role their mothers played in their upbringing varied, depending in part on the involvement of extended family. It was the stigma of maternal intellectual disability, rather than their mother's functional limitations, that posed the greatest challenge. Conclusion: Interviewees characterized their mothers and childhoods as different, yet ordinary. Understanding the social context, including but not limited to the availability of informal support, is critical to understanding the experience of children growing up with mothers with intellectual disability.