Patient safety events are common in healthcare. We can learn from other safety-critical industries that further incidents are most likely to be prevented where lessons are learned at the system level rather than looking to attribute blame for errors to individuals. Progress has been made over the last 20 years and relies on a positive safety culture (or just culture) where staff trust organisations to investigate safety events for learning rather than blame. Systems-based investigation models, such as the Systems Engineering Initiative for Patient Safety (SEIPS), help investigators to consider the full range of contributory factors across a system and to identify important findings. Considering the hierarchy of controls, recommendations should be targeted at system changes which are more likely to produce sustained safety improvements, rather than at individual behaviours or training, which are less likely to influence future safety. Systems-based safety investigations can positively influence safety culture in organisations.