This study examined the impact of information and communication technology integration on the teaching and learning of mathematics in selected secondary schools in Kampala District, Uganda, addressing a critical intersection between Uganda's Competency-Based Curriculum reform agenda which explicitly mandated the adoption of technology-supported, inquiry-driven, and collaborative learning approaches and the persistent challenge of low mathematics achievement that characterized Ugandan secondary education outcomes. Mathematics occupied a peculiar position in Uganda's secondary curriculum: it was simultaneously one of the most universally mandated subjects, one of the most consistently poorly performed in national examinations, and one of the subjects in which the pedagogical shift from rote memorization to conceptual understanding demanded by CBE was most consequential and most difficult to achieve without technological support. Drawing on a cross-sectional survey of 324 respondents comprising mathematics teachers, students across four secondary years, school ICT coordinators, and mathematics departmental heads from eight purposively selected secondary schools spanning urban and peri-urban Kampala, supplemented by classroom observation data from 54 mathematics lessons, this study employed descriptive statistics, hierarchy-of-controls ICT-mathematics integration analysis, bivariate Pearson correlation and chi-square association, and multilevel mixed-effects logistic regression to examine the determinants of ICT-enhanced mathematics learning effectiveness and the student outcome consequences of different ICT integration approaches. The findings demonstrated that interactive simulation and visualization tool use (β = 0.587, p < .001), formative digital assessment quality (β = 0.541, p < .001), and mathematics-specific software adoption (β = 0.512, p < .001) were the strongest independent predictors of improved mathematics achievement, while institutional factors including mathematics teacher ICT pedagogical training (OR = 6.84, p < .001), device-to-student ratio adequacy (OR = 5.41, p < .001), and school ICT integration culture (OR = 4.87, p < .001) were the strongest structural predictors. The study extensively benchmarks its infrastructure-capacity complementarity findings against Asiimwe et al. (2026), whose structural equation model demonstrated that digital infrastructure exerted a total effect of β = 0.661 on CBE implementation readiness — with β = 0.244 operating indirectly through teacher digital competence — arguing that the mathematics ICT integration context replicated this structural architecture with near-identical analytical force, and calling for mathematics-specific ICT pedagogical training, dynamic mathematics software investment, formative digital assessment tools, and school ICT leadership development as the priority interventions.