Background Family quality of life (FQoL) of families that have a child with severe to profound intellectual disabilities (SPID) is an important and emerging concept, however, related variables are inconclusive. Aim To gain a better understanding of variables related to the FQoL of families that have a child with SPID, variables related to the FQoL of families that have a child with intellectual disabilities (ID) were systematically reviewed. Methods and procedures A search strategy was performed in five databases. Critical appraisal tools were employed to evaluate the quality of both quantitative and qualitative studies. Data extraction and synthesis occurred to establish general study characteristics, variables, and theoretical concepts. Variables were categorised into four key concepts of the FQoL: systemic concepts, performance concepts, family-unit concepts and individual-member concepts. Outcomes and results A total of 40 studies were retrieved with 98 variables. Quality scores ranged from 7 to 13 (quantitative) and 5 to 13 (qualitative) out of 13 and 14 points, respectively. Five out of the 40 studies (13%) focused on individuals with SPID. Variables related positively or negatively to the FQoL, and were categorised within systemic concepts (n = 3); performance concepts (n = 11); family-unit concepts (n = 26); and individual-member concepts (n = 58). Conclusions and implications Several variables were found to be (inter)related to the FQoL of families that have a child with ID. A contrasting picture emerged regarding the impact of a disability in relation to transitional phases. However, studies which include families of children with SPID were minimal, therefore, it remained ambiguous to what extent the identified variables apply to these families.