Background and ObjectivesAn increasing number of children with diverse medical conditions are using long‐term noninvasive ventilation (NIV). This study examined the impact of demographic, clinical, and technology‐related factors on long‐term NIV adverse events in a large cohort of children using long‐term NIV.MethodsThis was a multicenter retrospective review of all children who initiated long‐term NIV in the province of Alberta, Canada, from January 2005 to September 2014, and followed until December 2015. Inclusion criteria were children who had used NIV for 3 months or more and had at least one follow‐up visit with the NIV programs.ResultsWe identified 507 children who initiated NIV at a median age of 7.5 (interquartile range: 8.6) years and 93% of them reported at least one NIV‐related adverse event during the initial follow‐up visit. Skin injury (20%) and unintentional air leaks (19%) were reported more frequently at the initial visit. Gastrointestinal symptoms, midface hypoplasia, increased drooling, aspiration and pneumothorax were rarely reported (<5%). Younger age and underlying conditions such as Down syndrome, achondroplasia, and Duchenne muscular dystrophy were early predictors of unintentional air leak. Younger age also predicted child sleep disruption in the short term and ongoing parental sleep disruption. Obesity was a risk factor for persistent nasal symptoms. Mask type was not a significant predictor for NIV‐related short‐ or long‐term complications.ConclusionsThis study demonstrates that NIV‐related complications are frequent. Appropriate mask‐fitting and headgear adaptation, and a proactive approach to early detection may help to reduce adverse events.