THE STUDY evaluated different extracts of Spirulina platensis using acetone, methanol, ethanol as well as water solvents for their antioxidant and antidiabetic potential. The results showed that all S. platensis extracts exhibited antioxidant activity by using DPPH (2, 2-Diphenyl-1-picrylhydrazyl), reducing power and total antioxidant capacity assays; in addition to their antidiabetic activity which was dependent on the used solvent. Among the tested extracts, S. platensis methanolic extract exhibited the highest antioxidant activity for all the tested assays and the maximum inhibitory effects for α-amylase (96.46 %) and α-glucosidase (97.42 %) diabetic enzymes. Spirulina methanolic extract showed no toxicity on normal cell lines using MTT assay. Gas chromatography–mass spectrometry (GC-MS) analysis of the methanolic extract revealed the presence of different bioactive compounds mainly phytol, 1-monolinoleoylglycerol trimethylsilyl ether, cholestan-3-ol, 2-methylene- (3β,5α) and fatty acids. These compounds might be acted synergistically to exert their obtained antioxidant and antidiabetic activity. For the in vivo study, administration of S. platensis methanolic extract (at 15 and 10 mg/Kg body weight (BW) caused antihyperglycemic activity by reducing the elevated blood glucose level. A remarkable decrease in different liver, kidney functions and hyperlipidemia related to diabetes were also detected. Furthermore, the methanolic extract treatment increased the body weight, total protein, albumin and hemoglobin levels as compared with the alloxan induced diabetic rats. Furthermore, treatment of diabetic rats with the extract improved liver and pancreas histopathological disorders related to diabetes. These results recommended using S. platensis methanolic extract in developing medicinal preparations for treatment of diabetes and its related symptoms.