Abstract Objectives: to construct and carry out content (CV) and response process (RPV) validation for a questionnaire to assess informal social support for the elderly. Method: a descriptive, observational, quantitative study was performed between January and December 2016 in the city of Natal (Rio Grande do Norte) and other locations in Brazil. The inclusion criteria were: proven experience in the area of social support (for experts) or 60 years of age or older and with preserved cognitive status (for the elderly). The CV stage evaluated the relevance of the items according to the general Content Validity Index (CVI) and per item as well as the assembly of the panel based on the observations of the experts. In the RPV stage, the understanding of the items by the target audience was evaluated. Results: the CV stage included a total of 40 interviewees. The overall CVI was 0.88 and only one item had a CVI considered poor. In the RPV stage 41 people were interviewed. Conclusion: the questionnaire exhibited good relevance for the proposed items and the observations of the interviewees allowed an approximation of the language used in the instrument to the language of the elderly.