Key Points Question Is adjuvant chemotherapy associated with a survival benefit for patients with locally advanced gastric cancer who underwent curative-intent gastrectomy after neoadjuvant chemotherapy? Findings In this cohort study of 462 patients with locally advanced gastric cancer from Western and Eastern countries, adjuvant chemotherapy was associated with significantly improved survival in patients with a lymph node ratio of at least 9% compared with those who did not receive adjuvant chemotherapy. Meaning These findings suggest that the lymph node ratio could be useful in adjuvant chemotherapy selection for locally advanced gastric cancer after neoadjuvant chemotherapy in future decision-making processes.