Background: The incidence of diabetes mellitus (DM) is increasing at an alarming rate globally. There is a need for suitable natural alternatives for its treatment, as the regular use of drugs causes several secondary health issues. Aim: This study aimed to quantitatively evaluate the phenol and flavonoid content; antioxidant and anti‑diabetic activity of fenugreek seeds and leaves in water and ethanolic extracts. Materials and Methods: Dried and powdered seeds and leaves of fenugreek were treated at different time and temperature combinations (100°C for 10 min; 80°C for 30 min; 60°C for 1 h; 37°C for 6 h; 24°C [room temperature] for 24 h; 100°C for 10 min followed by overnight soaking). Total phenolic content, total flavonoid content, 2,2‑Diphenyl‑1‑picrylhydrazyl (DPPH), and glucose uptake assays on 3T3‑L1 cell lines were performed on the extracts. Results: The results show that fenugreek leaves treated at 100°C for 10 min and overnight soaking yield extracts with the highest concentrations of desired phenols (46.08 ± 0.15 mg GAE/g sample) and flavonoid content (13.02 ± 0.44 mg/g sample) and antioxidant activity (DPPH) (45.41 ± 2.1%) with enhanced glucose uptake activity in 3T3‑L1 cell lines. Conclusion: The phenolic and flavonoid content, DPPH radical scavenging activity and antidiabetic activity was highest in the water extract of fenugreek leaves treated at 100°C for 10 min and subsequent soaking for 24 h before filtration as compared to the other protocols tested. Furthermore, water extracts showed enhanced activity as compared to the ethanol extracts in case of both seeds and leaves and in all the treatment combinations.