Objectives: In 2023, Bangladesh faced the largest dengue outbreak, resulting in 321,179 confirmed cases and 1705 fatalities. This study aims to characterize dengue fatalities and analyze their determinants and spatial influence. Methods: Using data from the Management Information System of the Ministry of Health and Family Welfare, we characterized dengue mortality and conducted a linear regression analysis to determine the impact of age groups and gender on case fatality rate (CFR). We used a geographically weighted Poisson regression model to assess the spatial influence and impact of population factors. Results: Women had a higher CFR than men (0.75% vs 0.38%, P <0.05). Among the recorded deaths, 74% (n = 1262) developed dengue shock syndrome, 17% (n = 290) expanded dengue syndrome, and 7% (n = 119) dengue hemorrhagic fever. The 10-year age groups significantly impacted CFR (estimate: 0.03, P <0.01), suggesting that each additional decade increased CFR by 30%, whereas gender was insignificant. Higher deaths were observed in the southern regions, whereas spatial clusters were primarily concentrated around Dhaka City, the epicenter of the outbreak. Substantial effects from neighboring districts were also identified. Conclusions: Bangladesh’s 2023 dengue outbreak resulted in significant mortality, particularly, among older age groups. Fatalities were clustered in Dhaka City and its neighboring districts, especially in the south.