Type III open tibial fracture is the commonest type of open tibia fracture. The aim of this study was to determine the outcome of Gustilo-Anderson type III open tibial fracture managed with external fixator. Patients that presented with Gustilo-Anderson type III open tibial fractures were recruited. Patients with bone pathology, prior debridement and concomitant spinal cord injury were excluded. Ethical approval and informed consent were obtained. A structured proforma was used to collect the participant’s socio-demographic data, time of injury, fracture location, interval and number of debridement, need for skin graft or flap, duration of hospital stay, outcome of treatment, complications and events at follow-up. Wound biopsy was taken and processed for microscopy, culture, and sensitivity. Delayed union was diagnosed when the fracture united between 4-6 months. Non-union was defined as a varus or valgus angulation of >5 degrees or anterior or posterior angulation of >10 degrees. Patients were followed up for 6 months. Chi square was used to determine association between categorical variables. SPSS 20 was used for analysis. Significance was p value <0.05. Of 35 patients, males were 22 (62.9%) while females were 13 (37.1%) and mean age was 38 years. Average interval between injury and presentation was 14.5 hours. Fourteen (40%) patients had type IIIA, 18 (51.4%) patients had type IIIB while 3 (8.6%) patients had type IIIC. Mean time to fixation was 59.2 hours. Wound infection, malunion, delayed union, pin loosening and compartment syndrome were found in 42.9%, 21.3%, 21.3%, 11.5% and 1.6% respectively. Infection rate was significantly positively correlated with grade of fracture (p=0.04) and time to debridement (p=0.018). A significant association between the mechanism of injury and associated injury (p=0.027) but not mechanism of injury and grade of type III fracture (p=0.292). Significant difference between the duration of hospital stays and categories of type III fractures (p = 0.026) but not associated injury (p=0.403). No significant difference in location of fracture and time of union (p=0.723). Type III fractures managed with external fixator is associated with some complications among which infection is the commonest and delay in treatment is associated with higher risk. Post-debridement microscopy and culture is a better predictor of wound infection.