Background: Neuroendocrine carcinomas of the gallbladder (NECs-GB) are rare tumors, accounting for <0.2% of all neuroendocrine carcinomas of the gastrointestinal tract. They originate from the neuroendocrine cells of the gallbladder epithelium with associated intestinal or gastric metaplasia. The current study is the largest study from the SEER database on NECs-GB that aims to elucidate the demographic, clinical, and pathologic factors influencing the prognosis and comparative survival analysis of different treatment modalities. Methods: The data from 176 patients with NECs-GB was abstracted from the Surveillance Epidemiology and End Result (SEER) database (2000–2018). Multivariate analysis, non-parametric survival analysis, and a chi-square test were used to analyze the data. Results: NECs-GB had a higher incidence amongst females (72.7%) and Caucasians (72.7%). Most patients had surgery only (N = 52, 29.5%), (N = 40) 22.7% had chemotherapy only, and (N = 23) 13.1% had chemotherapy with surgery. Only (N = 17) 9.7% had trimodaltiy (surgery, chemotherapy, and radiation therapy), and for (N = 41) 23.3% the status of chemotherapy was unknown, and these cases had neither radiation nor surgery. Conclusion: NECs-GB more frequently affects Caucasian females after the 6th decade of life. The combination of surgery, radiation, and adjuvant chemotherapy was associated with better long-term (5 years) outcomes, while surgery alone was associated with better short-term (<2 years) outcome survival.