Naturally occurring radioactive materials (NORMs) in lake sediments may contribute to human radiation exposure through multiple environmental pathways, making periodic radiological assessment important for environmental protection. This study conducted a screening-level radiological risk assessment of Jabi Lake, Abuja, Nigeria, using activity concentrations of 226Ra, 232Th, and 40K measured from a one-time sediment sampling campaign and the RESRAD-Onsite computer code. Gamma spectrometric analysis showed that the measured radionuclide concentrations and the corresponding radium equivalent activity were below the recommended UNSCEAR limits, indicating that the present radiological status of the lake sediments is unlikely to pose significant health concerns. Conservative RESRAD-Onsite simulations identified fish consumption as the dominant potential exposure pathway and indicated increased radiation dose and excess lifetime cancer risk under hypothetical long-term exposure scenarios assuming persistent radionuclide concentrations. These results represent conservative screening-level estimates rather than predictions of future environmental conditions. The study provides baseline radiological data for Jabi Lake and demonstrates the value of integrating environmental measurements with conservative modelling to support preliminary risk evaluation and future environmental monitoring.