Objective: This study aimed to investigate the incidence, risk factors, and clinical significance of endograft migration (EM) following thoracic endovascular aortic repair (TEVAR). Methods: Consecutive patients undergoing TEVAR at a tertiary aortic referral centre between February 2004 and January 2025 were reviewed, with clinical and radiological follow-up until April 2026. Patients with at least 6 months of computed tomography angiography surveillance were included. EM was defined as endograft displacement ≥10 mm relative to fixed anatomical landmarks, or any displacement associated with symptoms or requiring treatment. Predictors of proximal endograft distal migration and distal endograft proximal migration were evaluated using univariable and multivariable logistic regression. Time to first EM was analysed using Kaplan–Meier methods. Results: Of 125 patients, 91 were male (72.8%), with mean age 59 years (range 15–87). The most common indications were type B aortic dissection (n = 41, 32.8%) and thoracic aortic aneurysm (n= 41, 32.8%). EM occurred in 33 patients (26.4%) over median follow-up of 73.7 months (IQR 37.0-109.0). Freedom from EM was 88.2% at 1 year, 75.2% at 3 years, and 68.4% at 5 years. Aortic elongation was associated with proximal endograft distal migration (OR 2.08, 95% CI 1.46–3.27; p < .001) and distal endograft proximal migration (OR 2.59, 95% CI 1.77–4.21; p < .001). Proximal-first deployment was independently associated with proximal endograft distal migration (OR 12.08, 95% CI 2.11–230.76; p = .022). Prompted by imaging surveillance, six patients with EM (18.2%) underwent EM-related reintervention; there was no EM-related mortality. Conclusion: EM after TEVAR was common on imaging surveillance, most occurring within the first two years. Aortic elongation was the most consistent anatomical predictor, while a proximal-first deployment in multi-device repairs was a strong, modifiable procedural risk factor.