Background: The objective of the present systematic study was to analyze and characterize the gastric vein (GV) variations to understand their significance within clinical contexts, particularly in gastric and liver surgeries and managing conditions associated with the portal vein system. Methods: We conducted a systematic review, examining various databases, including Medline, Scopus, Web of Science, Google Scholar, CINAHL, and EMBASE, up to April 2025. Two independent authors conducted the literature search, selected pertinent studies, and extracted relevant data. The methodological quality of the studies was evaluated utilizing the Assessment Tool for Anatomical Studies (AQUA). The pooled prevalence was estimated through the application of a random effects model. Results: Among the 279 articles reviewed, 11 studies were ultimately incorporated into the systematic analysis, encompassing 47,993 subjects. The pooled prevalence of GV variants was determined to be 8.32%, revealing considerable heterogeneity (I2 = 98.92%). A subgroup analysis showed a greater prevalence of GV variants in diagnostic imaging studies than in cadaveric studies, with a higher frequency observed in males than in females. Conclusions: The morphological variability of the GVs holds clinical significance, as it may significantly impact the management of abdominal disorders, particularly during surgical and endovascular interventions. This study emphasizes the necessity of thorough preoperative evaluations to identify these variations, thereby minimizing surgical complications and enhancing therapeutic outcomes for patients suffering from gastric and portal vein system disorders. Integrating advanced imaging techniques into clinical practice may facilitate improved surgical and therapeutic planning.