Introduction: The Japanese guidelines for endoscopic submucosal dissection (ESD) of Barrett’s esophageal adenocarcinoma (BEA) recommend image-enhanced magnifying endoscopic examination for diagnosing the lateral extent of superficial esophageal adenocarcinoma. The Japan Esophageal Society Barrett’s Esophagus (JES-BE) classification is proposed recently and is useful in terms of diagnostic accuracy. In this study, we retrospectively examined the usefulness of the JES-BE classification for differential diagnosis and determination of the extent of BEA originating in short-segment Barrett’s esophagus. Methods: The study reviewed 51 lesions which underwent ESD for BEA. The circumference of the esophagogastric junction was divided into four parts, and the lesions were divided into those in the right anterior portion (RA group; n = 33) and those in other portions (non-RA group; n = 18). Clinicopathological characteristics and clinical outcomes were compared between the two groups. Results: JES-BE classification findings as “dysplasia” were seen in 48 out of 51 (94.1%) BEA lesions retrospectively. There was no significant difference in histological type, tumor depth, lymphovascular invasion, or the proportion of tumors with a positive or unknown horizontal or vertical margin status between the groups. The proportion of tumors with type 0-I morphology was significantly higher in the RA group (p = 0.023). The tumor size was significantly greater in the RA group (p = 0.034). According to the JES-BE classification, 31 lesions (93.9%) in the RA group and 17 lesions (94.4%) in the non-RA group were diagnosed as dysplasia. There was also no significant difference in the rate of consistency between the endoscopic and histopathological findings on the lateral extent of the lesion (90.9% vs. 83.3%; p = 0.612). Discussion/Conclusions: The JES-BE classification may be useful for determining the extent of BEA.