Abstract Background Second-line therapy has consistently demonstrated survival benefit if compared with best supportive care; however, there is limited evidence whether further lines of treatment may improve the prognosis of advanced gastric cancer (AGC) patients. Materials and Methods Starting from a real-world cohort of 868 AGC patients, we retrospectively analyzed baseline parameters, tumor characteristics, and treatment data of those treated with at least three lines. Categorical features were described through cross-tables and chi-square test. We explored the impact of treatment intensity and progression-free survival (PFS) experienced in previous lines on PFS and overall survival in third-line by uni- and multivariate Cox regression models and described by Kaplan-Meier estimator plot with log-rank test. Results Overall, 300 patients were included in the analysis. The most common site of primary tumor was gastric body; 45.3% of cancers had an intestinal histotype, 14% were human epidermal growth receptor 2 positive. In third-line, 45.7% of patients received a single-agent chemotherapy, 49.7% a combination regimen. Patients who had experienced a first-line PFS ≥6.9 months had a better prognosis compared with those who had achieved a shorter one. Consistently, a second-line PFS ≥3.5 months positively influenced the prognosis. Patients receiving a third-line combination regimen had better outcomes compared with those treated with a single-agent chemotherapy. Conclusion Our real-world study confirms that selected AGC patients may receive third-line treatment. Longer PFS in previous lines or a more intense third-line treatment positively influenced prognosis. Further efforts are warranted to define the best therapeutic sequences, and to identify the optimal candidate for treatment beyond second-line.