Background: The Family Network Method -- Intellectual Disability (FNM-ID) was used to compare perspectives of people with mild intellectual disability and their support workers on family networks of people with intellectual disability. Method: 138 participants with mild intellectual disability and support workers were interviewed, using the FNM-ID. Paired t-tests were used to examine differences in perspectives. Multiple regression analyses were used to examine divergence in perspectives. Results: People with mild intellectual disability perceived their family networks to be larger and to provide more support than support workers did. Living in a residential setting and having higher levels of externalising behaviour were associated with differences in perspectives, whereas a higher level of internalising behaviour was associated with more similar views. Conclusions: Individuals with intellectual disability and support workers are unlikely to provide the same information about family networks of people with mild intellectual disability. Behavioural and emotional problems were associated with divergence in perspectives.