Supracondylar fractures of the humerus (SCFH) are the most common type of paediatric elbow fractures. Due to beliefs that non-operatively managed SCFH may displace further from the original position, they are monitored with repeated radiographs and a large number are unnecessarily surgically pinned. Very limited evidence currently exists to support these beliefs. This study aimed to determine the incidence of late “significant” displacement (requiring surgical management) of non-operatively managed paediatric SCFH, and whether they necessitate close radiographic follow-up. Patients aged ≤16, with a SCFH, were included in this retrospective cohort study. All were initially managed non-operatively with at least one follow-up radiograph within six weeks of injury. Data from four consecutive years (2013–2016) was collected using the hospital's radiology database. Two observers independently analysed patient radiographs and classified fractures by the Gartland and AO systems. The incidence of late displacement was determined using follow-up radiographs and clinic notes. Of the 164 patients included in the study, one patient (Gartland Type II, AO Type III) suffered late displacement at two weeks, requiring surgical fixation. One further patient (AO Type II) had a persistent cubitus varus deformity (Baumann's angle 90°), with no long-term functional deficit. Incidence of late displacement was 0.6% (n=1). Our findings suggest that stable Gartland Type I/AO Type I and II fractures do not require repeated radiographic follow-up. However, some Gartland Type II/AO Type III fractures require monitoring. This could considerably reduce the financial costs for the healthcare system, and inconvenience to families, associated with repeated follow-ups.