Abstract Purpose Non-union is a significant complication following open diaphyseal tibia fractures. Management can be complex and unpredictable. Several principles must be addressed often in combination to achieve union. The aim of this study is to report on the characteristics, management and eventual outcome of non-united open tibial fractures over a 12-year period from a level I trauma centre. Methods This is a retrospective observational study of all adults (age 18 years and older) presenting to a level 1 trauma centre with a diaphyseal tibia fracture. Non-union was diagnosed using the standard FDA definition of incomplete union by 9 months or no progress to union in the preceding 3 months. Injury and patient demographics in addition to all interventions and complications were recorded for each patient. Results Forty three cases of diaphyseal non-union were identified from 2008 to 2019. Only the presence of peripheral vascular disease demonstrated a statistically significant association with the development of non-union. In 44% of cases, more than one additional operation was required to achieve union. Successful union was achieved in 90% of cases with 74% of patients returning to full pre-injury function without complication. Conclusion Management of non-union is a complex problem which requires a multifaceted and bespoke approach. We have included an algorithm to help guide decision making based on our institutional experience. A satisfactory result is achievable in the majority of patients.