Background: Researchers, professionals, and families have shown increasing concern with the family quality of life (FQoL) of people with intellectual disability (ID) and their families. The goals of this research were (a) to explore how Spanish families understand FQoL by developing 2 different measurement tools for families with a member with ID under and over 18 years old, and (b) to provide 2 diagnostic instruments that will be useful for designing action plans. Method: The study comprised 4 stages: (a) focus groups, (b) expert assessment, (c) pilot study, and (d) normalisation and standardisation. The data were collected in 5 regions in Spain, and 1,205 families with a member with ID took part in the normalisation and standardisation of the scales. Results: Both FQoL scales were consistent and have valid psychometric characteristics. Conclusions: The scales have a diagnostic purpose for use in designing action plans aimed at producing significant changes in families' lives.