This study examined the factors influencing the utilization of family planning services among women of reproductive age at Kisenyi Health Centre IV, Kampala District. Despite the availability of family planning services and their well- documented health and socioeconomic benefits, uptake among women in urban low-income settings such as Kisenyi remains suboptimal. The study investigated how knowledge and awareness, service accessibility, attitudes and beliefs, and spousal or partner support relate to the utilization of family planning services. A cross-sectional survey design with a mixed-methods approach was adopted, and data were collected from 200 women of reproductive age and 20 health workers using structured questionnaires and key-informant interviews. Descriptive statistics, Pearson correlation, and regression-based path analysis were used. The results revealed a strong positive and significant relationship between the identified factors and family planning utilization (r = 0.66, p < 0.01), with the factors jointly explaining 63.0% of the variance in utilization (R² = 0.630). Service accessibility and knowledge and awareness emerged as the strongest predictors. The study concludes that improving knowledge, accessibility, and partner involvement significantly enhances family planning utilization and recommends targeted health education, strengthened service delivery, and male involvement strategies.