Aim: To evaluate the Inhibitory effect of aqueous extracts of Sacoglottis gabonensis on weight gain in Swiss mice exposed to aspartame. Study Design: The study was a completely randomized design employing relevant statistical tools for analysis and interpretation. Place and Duration of Study: The study was carried out in the Department of Animal and Environmental Biology, Rivers State University. The experiment lasted for 90 days between April and June 2022. Methodology: A total of 30 adult male Swiss mice (mean weight 23.07±0.12g) were divided into six groups of five animals each. Group A was the negative control which received neither Sacoglottis gabonensis nor Aspartame, group B was the positive control which received 50mg/kg/bw/day of Aspartame only, group C received 50mg/kg/bw/day of Aspartame with 250mg/kg/bw/day of aqueous bark extract of S. gabonensis, group D received 50mg/kg/bw/day of Aspartame with 250mg/kg/bw/day of aqueous leaf extract of S. gabonensis, while groups E and F received 50mg/kg/bw/day of Aspartame with a combination of 250mg/kg/bw/day and 500mg/kg/bw/day of extracts of S. gabonensis bark and leaf extracts respectively. The experimental animals were weighed twice weekly for 30, 60 and 90 days duration and recorded to the nearest 0.01g. Mean weight from each duration was taken and subjected to statistical analysis using Statistical Analyses System SAS 9.4 Results: There was significant increase (p<0.05) in weight in the 30, 60 and 90-days exposure periods in group B. The groups that received the combination of aspartame and S. gabonensis particularly at higher doses showed a significant decrease in weight across the exposure periods when compared to the group that received aspartame only and the control group. Conclusion: This result suggests that S. gabonensis reduced aspartame-induced weight gain, indicating its potential benefits for weight management. Further research is needed to explore the underlying mechanisms and health implications.