(1) Background: Oncological gastrectomy requires complex multidisciplinary management. Clinical pathways (CPs) can potentially facilitate this task, but evidence related to their use in managing oncological gastrectomy is limited. This study evaluated the effect of a CP for oncological gastrectomy on process and outcome quality. (2) Methods: Consecutive patients undergoing oncological gastrectomy before (n = 64) or after (n = 62) the introduction of a CP were evaluated. Assessed parameters included catheter and drain management, postoperative mobilization, resumption of diet and length of stay. Morbidity, mortality, reoperation and readmission rates were used as indicators of outcome quality. (3) Results: Enteral nutrition was initiated significantly earlier after CP implementation (5.0 vs. 7.0 days, p < 0.0001). Readmission was more frequent before CP implementation (7.8% vs. 0.0%, p = 0.05). Incentive spirometer usage increased following CP implementation (100% vs. 90.6%, p = 0.11). Mortality, morbidity and reoperation rates remained unchanged. (4) Conclusions: After implementation of an oncological gastrectomy CP, process quality improved, while indicators of outcome quality such as mortality and reoperation rates remained unchanged. CPs are a promising tool to standardize perioperative care for oncological gastrectomy.