The goal of the current study was to create, develop, and assess a polyherbal tea granule formulation that combined Aegle marmelos (Belpatra), Momordica charantia (Karela), Tinospora cordifolia (Guduchi), Eugenia jambolana (Jamun), and Stevia rebaudiana (Stevia) for possible antidiabetic benefits. These traditionally used herbs have all demonstrated potential as antidiabetic agents, and their combined effects may be more potent. Nine formulations (F1–F9) with varying herb quantities were made using solvent extraction, and the findings were standardized using HPLC. The optimized formulation (F5) was evaluated for its phytochemical content, antioxidant activity (DPPH, FRAP), antidiabetic activity (in vitro inhibition of α-amylase and α-glucosidase, in vivo streptozotocin-induced diabetic rats), sensory qualities (taste, aroma, color, overall acceptability), and physical attributes (moisture content, bulk density, particle size).