Introduction Treatment for stage IIIA N2 Non-Small Cell Lung Cancer (NSCLC) typically involves a combination of chemotherapy, radiotherapy and surgery but the optimal sequencing is not determined. Local recurrence rates following surgery remain high and the role of post-operative radiotherapy (PORT) in N2 disease is unclear. This meta-analysis aims to determine whether PORT provides additional survival advantage beyond observation for patients with Stage IIIA N2 disease who have undergone complete surgical resection and received adjuvant chemotherapy. Methods All studies comparing adjuvant chemotherapy and PORT versus adjuvant chemotherapy alone after curative surgical resection for stage IIIA N2 NSCLC were included. Meta-analysis was performed using random effects modelling in accordance with MOOSE guidelines. Subgroup analysis, heterogeneity and risk of bias were assessed, with meta-regression to determine the effects of patient and tumor characteristics on outcomes. Results Ten studies with a pooled dataset of 18077 patients (5453 PORT, 12624 no PORT) were included. PORT significantly improved both overall and disease free survival at 1 year (OS: HR=0.768; DFS: HR=0.733), 3 years (OS: HR=0.914; DFS: HR=0.732) and 5 years (OS: HR=0.898; DFS: HR=0.735, all p<0.0001). These effects were independent of specific patient or tumor characteristics. Discussion This study demonstrates a significant disease-free and overall survival benefit from the addition of PORT following adjuvant chemotherapy. We advocate the consideration of PORT for such patients following specialist multidisciplinary assessment and comprehensive discussion of the benefits and risks of treatment.