(1) Background: Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) in the remnant stomach or gastric tube is not yet widespread and few studies have compared the short-term and long-term outcomes with radical surgery. (2) Methods: A total of 73 consecutive patients with EGC in the remnant stomach or gastric tube who underwent ESD or radical surgery between October 2009 and October 2020 were retrospectively analyzed in this study. Baseline characteristics, post-operative complications, quality of life (QOL), recurrence rate, overall survival (OS) and disease-free survival (DFS) were compared between the ESD and surgery groups. (3) Results: Among the 73 patients with EGC in the remnant stomach or gastric tube, 48 (65.8%) underwent ESD and 25 (34.2%) underwent surgery. The operation time (p = 0.000) and post-operative hospital stay (p = 0.002) of the ESD group were significantly shorter than those in the surgery group. The incidence of post-operative complications in the ESD group was significantly lower than that in surgery group (p = 0.001). The ESD group had significantly better functional scale scores and lower rates of fatigue, pain, appetite loss, financial difficulties, dysphagia, eating restrictions, hair loss, and poor body image than the surgery group. There was no significant difference in OS or DFS between the ESD and surgery groups (p = 0.124 and 0.344, respectively). (4) Conclusion: ESD can significantly shorten the operation time and hospital stay, reduce surgical complications, and provide better QOL for patients with EGC in the remnant stomach or gastric tube, and its long-term prognosis is no shorter than that of radical surgery.