Background: Family planning (FP) services are vital for reproductive health, particularly for individuals living with HIV. Integrating FP into HIV care can increase contraceptive uptake, reduce unintended pregnancies, and prevent mother-to-child transmission of HIV. This study examined FP uptake and utilization among HIV-positive patients attending the Haematology/ART clinics at Lagos State University Teaching Hospital (LASUTH). Materials and Methods: A cross-sectional study was conducted among HIV-positive individuals receiving care at LASUTH. Data were collected using structured questionnaires covering socio-demographic information, FP awareness, service utilization, and barriers to uptake. Statistical analyses, including chi-square tests, were used to assess associations between demographic factors, awareness, and FP utilization. Results: The findings revealed a significant association between gender, marital status, employment status, ethnicity, and FP awareness. Married and employed respondents demonstrated higher awareness, and awareness was strongly associated with FP uptake. Respondents aware of FP services were significantly more likely to use contraceptives than those unaware. Despite this, several barriers were reported, including spousal opposition, religious objections, misconceptions about contraceptive side effects, and limited accessibility. These barriers influenced both awareness and actual uptake of services. Conclusion: This study underscores the importance of integrating FP into HIV care to enhance accessibility and utilization. Increasing awareness, promoting male involvement, and addressing cultural and religious misconceptions are key strategies to improve uptake. Integrating FP into ART clinics aligns with global recommendations for comprehensive HIV care and can improve reproductive health outcomes while reducing HIV transmission risks. Tailored interventions and evidence-based policies are needed to strengthen FP adoption among people living with HIV in Lagos State and similar settings.