Background: Uganda maintains one of the world's highest total fertility rates (TFR) at 5.4 children per woman, presenting a paradox of significant demographic potential juxtaposed against persistent maternal mortality, limited contraceptive uptake, and deep socioeconomic inequalities. This study examined the determinants of Uganda's high fertility, the pathways through which socioeconomic and health system factors influence reproductive behavior, and the extent to which high fertility can be channeled into productive demographic dividends. Methods: A mixed-methods cross-sectional design was employed, drawing on a nationally representative sample of 2,496 women of reproductive age (15–49 years) from all four regions of Uganda, supplemented by 48 focus group discussions (FGDs) with purposively sampled community members. Quantitative data were analysed using univariate, bivariate, and structural equation modelling (SEM) techniques, while qualitative data were analysed using thematic content analysis. Statistical significance was set at p < 0.05 with 95% confidence intervals reported throughout. Results: The mean TFR was 5.4 (SD=2.1), with marked regional and socioeconomic variation ranging from 7.12 in the Northern region to 3.41 in Kampala. Bivariate analyses revealed statistically significant associations between TFR and maternal education (p