Objectives: The aim of this study was to assess the perception of quality of life of patients with spinal muscular atrophy (SMA) and investigate whether there is a correlation between patients' perception and that of their carers. Methods: Cross-sectional analytical observational study. In the first part, socioeconomic, demographic, clinical, and treatment information were collected from patients diagnosed with SMA, regardless of type, sex, or age. SMA type1 does not sit; SMA type 2 sits; SMA type 3 walks; and SMA type 4 begins in adulthood. In the second part of the study, patients aged between 2 and 25 years and their caregivers responded to the Pediatric Quality of Life Inventory 4.0 questionnaire. Results: Of the 235 families recruited, 167 were eligible to respond to the questionnaire, 115 caregivers and 49 patients were included. The results point to a different perception of quality of life between patients and caregivers. Patients with SMA type 2 perceive more impaired physical and emotional capacity compared to SMA type 3 and1, respectively. As for caregivers, the perception of quality of life in relation to physical and social capacity and the total score are worse for patients with SMA type1 compared to other types. Perceptions correlate with emotional capacity in SMA type 2 and the total aspect in SMA type 3. Conclusions: Patients with SMA type 2 had a worse perception of their quality of life than other patients. Perception differed between patients and their caregivers, with the former having a better perception than the latter.