This study examined the relationship between monitoring and evaluation practices and project performance within Kampala Capital City Authority (KCCA), Uganda, addressing a persistent public-sector management concern: that substantial public investment in urban infrastructure, service delivery, and development projects had not always translated into commensurate improvements in project completion rates, budget adherence, quality of output, or beneficiary satisfaction. As the statutory body responsible for administering Uganda's capital city, KCCA managed a large and diverse project portfolio spanning road construction and rehabilitation, drainage and flood-control works, market redevelopment, solid waste management infrastructure, public health facility upgrades, and revenue and citizen-service digitisation initiatives — a portfolio whose scale and technical diversity placed correspondingly high demands on the authority's monitoring and evaluation systems to track progress, identify implementation risks early, and support evidence-based project management decisions. Drawing on a cross-sectional survey of 268 respondents comprising KCCA project managers and engineers, monitoring and evaluation officers, divisional technical staff across Kampala's five administrative divisions, contractor and consultant representatives, and a sample of project beneficiaries drawn from six recently completed or ongoing projects, this study employed descriptive statistics, hierarchy-of-controls monitoring-and-evaluation capability assessment, bivariate Pearson correlation and chi-square association, and multilevel mixed-effects logistic regression to examine the determinants of strong project performance. The findings demonstrated that monitoring data quality and timeliness (β = 0.612, p < .001), stakeholder and beneficiary feedback integration (β = 0.554, p < .001), and corrective action responsiveness (β = 0.527, p < .001) were the strongest independent predictors of project performance, while structural factors including monitoring and evaluation staff technical capacity (OR = 6.34, p < .001), management information system adequacy (OR = 5.47, p < .001), and top management use of monitoring data in decision-making (OR = 4.91, p < .001) were the strongest institutional predictors. The study calls for strengthened KCCA monitoring and evaluation staffing and technical training, investment in an integrated project management information system, formalised beneficiary feedback mechanisms, and stronger institutional linkage between monitoring findings and management decision-making as the priority interventions for improving project performance across KCCA's development portfolio.