Background: Non-invasive ventilation (NIV) for respiratory failure and airway clearance is an established intervention in cystic fibrosis (CF), but its therapeutic benefit on lung function and survival remains under-investigated. Methods: Using data from the UK CF Registry between 2007 and 2015, we explored the patterns of NIV use, and assessed changes in mean percent predicted FEV1 (ppFEV1) prior to and after NIV use, and the survival of patients on NIV. Results: Among 11,079 patients, 1107 had at least one record of NIV treatment. Incidence and prevalence of NIV was lower in children and followed non-linear temporal patterns. Adjusting for other risk factors, ppFEV1 rose by 0.70 (95%CI: -0.83, 2.24) after first NIV use in children. In adults with a low ppFEV1 (<40%) at initiation of treatment, NIV increased mean ppFEV1 by 2.60 (95% CI: 0.93, 4.27). Our analysis showed that NIV initiation is associated with an increased risk of death/transplant in both children (HR = 2.47; 95%CI: 1.20–5.08) and adults (HR = 1.96; 95% CI: 1.63–2.36) but effect was attenuated in children with low ppFEV1 (<40%). Conclusions: NIV usage in CF improves spirometric values but does not benefit survival. Further studies are required to better understand survival outcomes and ultimately improve NIV outcomes in CF.