The anti-aging effect and underlying mechanism of oleuropein were herein investigated. A diet-induced oxidative stress study model was established by administrating 0.11 mol•L−1 glucose to Caenorhabditis elegans. The effect of increasing doses of oleuropein on the lifespan and lipid metabolism of C. elegans, as well as on oxidative stress-related parameters was evaluated. Oleuropein administered at 50, 100, and 200 μmol•L−1 significantly prolonged the lifespan of C. elegans in a dose-dependent manner by 23.36%, 32.51%, and 42.01%, respectively. Additionally, body width and area were reduced, whereas the frequencies of body and head swinging were increased. The attenuation of fat accumulation in C. elegans by oleuropein was confirmed through Oil Red O/Nile Red staining, and decreased levels of triglyceride and free fatty acid were detected. Furthermore, levels of reactive oxygen species, lipofuscin, and malondialdehyde decreased upon oleuropein exposure, whereas the activity of superoxide dismutase (SOD) and catalase increased. At 200 μmol•L−1 oleuropein, daf-16, lipl-4, and sod-3 levels were upregulated by 2.47, 1.39, and 2.20-fold, respectively, and the nuclear translocation ratio of DAF-16 in TJ356 C. elegans was reduced by 56.80%. In contrast, no effects on the lifespan, triglyceride content, or SOD activity were observed in CF1038 C. elegans. In conclusion, oleuropein can effectively extend the lifespan of C. elegans and exert anti-aging effects via daf-16-mediated modulation of lipid metabolism homeostasis and antioxidant stress responses. These findings provide a solid theoretical foundation for the translational development and practical application of oleuropein.