ObjectivesThis study aimed to investigate the efficacy of prophylactic steroid administration in preventing post‐endoscopic submucosal dissection (ESD) esophageal stricture and to determine risk factors for these strictures.MethodsPatients who underwent ESD for superficial esophageal neoplasms with a mucosal defect affecting >75% of the esophageal circumference between January 2011 and August 2016 were eligible. Patients were classified into three groups, including ESD‐alone group (n = 22), oral steroid group (n = 25) and intralesional steroid injection group (n = 6). Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors for esophageal stricture.ResultsThe stricture rate was 50.0%, 20.0% and 33.3% in the ESD‐alone group, oral steroid group and steroid injection group, respectively. Patients treated with steroids had a significantly lower stricture rate than the ESD‐alone group (22.6% vs 50.0%, P = 0.046). Additionally, oral steroid group had a significantly lower stricture rate than the ESD‐alone group (P = 0.037). Multivariate analysis revealed that the extent of the circumferential mucosal defect was a significant risk factor for post‐ESD strictures (odds ratio [OR] 13.015, 95% confidence interval [CI] 2.257‐76.077, P = 0.004). The administration of steroids (OR 0.108, 95% CI 0.020‐0.578, P = 0.009), specifically oral steroids (OR 0.109, 95% CI 0.019‐0.622, P = 0.013), was associated with prevention of post‐ESD strictures.ConclusionOral steroid prophylaxis appears to be a safe and effective treatment in preventing post‐ESD stricture and improving patients' quality of life.