BACKGROUND: Validated instruments are needed to assess the delivery of patient-centred care (PCC) to people with intellectual disabilities (PWIDs) needing 24-h care in residential settings. Eight dimensions of PCC have been identified: taking patients' preferences into account; access to care; emotional support; physical comfort; information and education; involvement of family and friends; coordination of care; and continuity and secure transition. Objective of this study is to validate an instrument to assess these eight PCC dimensions among informal caregivers of PWIDs in residential settings (institutional settings as well as group homes in the community). The original 24-item instrument was developed and validated among professionals providing care to PWIDs. METHODS: This study was conducted in a disability care centre in the Netherlands. All informal caregivers of PWIDs living in institutional settings or group homes in the community in need of 24-h care were invited to participate (n = 941). The response rate was 31% (n = 289). We tested the instrument using structural equation modelling, and examined its validity and reliability. RESULTS: Confirmatory factor analyses revealed good indices of fit and overall internal consistency, as represented by Cronbach's alpha values. All eight dimensions of PCC were related positively to satisfaction with care (all p ≤ 0.001). As expected, informal caregivers were less critical of PCC and its underlying dimensions, except for information and education, than were professionals working in the same disability care centre. CONCLUSIONS: The psychometric properties of the 24-item PCC instrument for informal caregivers (PCC-IC) were satisfactory, indicating that the PCC-IC is valid and reliable for the assessment of the eight dimensions of PCC among informal caregivers of PWIDs in residential settings.