Family carers play an important role supporting individuals with intellectual and developmental disabilities (I/DD) into adulthood. Funders of services often desire this ongoing involvement by family members yet they rarely collect data about family carers. As policy makers and planners are increasingly recognizing the need for information related to indicators of system performance, a scoping review was conducted to identify system‐wide information needed about family carers of adults with I/DD that would help improve the quality of service provided. A final review of 87 research articles was organized in terms of service use, service need, and permanency planning by family carers of adults with I/DD. Service use and need were associated with the presence of challenging behaviors among individuals with I/DD as well as carer demographics and health status. In addition, carers' subjective view of how well they think they can provide for their child in the future was an important determining factor of service need. Permanency planning was associated with child level of functioning as well as parent income, social support, and compound caregiving demands. Studies highlighted the importance of measuring family carers' mental and physical health and their perceptions of the adequacy of services received. Considered also were methodological limitations, highlighting considerations for future system monitoring. Methodological limitations of studies reviewed include reliance on cross‐sectional data, samples consisting of families already receiving at least some services, and little information about the process of seeking and obtaining services. Areas to target in future system monitoring include information on who needs services, what services are needed, families' perceptions of the caregiving experience and families' experiences waiting for services over time. Understanding the experiences of family carers as seekers of formal services can help inform policy and practice.