One of the therapeutic approaches in treating diabetes is to reduce postprandial hyperglycemia by inhibiting major carbohydrate hydrolyzing enzymes. In the present study, crude extracts of marine seaweed,Turbinaria ornata, were tested for their antidiabetic potential using enzyme inhibitory assays (α-amylase,α-glucosidase, and dipeptidyl peptidase-IV). Among the tested extracts, methanol and acetone extracts showed significant inhibitory effects onα-amylase (IC50250.9μg/mL),α-glucosidase (535.6μg/mL), and dipeptidyl peptidase-4 (55.2μg/mL), respectively. Free radical scavenging activity of these extracts was analyzed using DPPH assay (65%). Extracts were tested forin vitrotoxicity using DNA fragmentation assay, haemolytic assay, and MTT assay. None of the extracts showed toxicity in tested models. Furthermore, GC-MS analysis of lead extracts showed the presence of major compounds, hentriacontane, z, z-6, 28-heptatriactontadien-2-one, 8-heptadecene, and 1-heptacosanol. Our findings suggest thatTurbinaria ornatacan be used as a potential source for furtherin vivostudies in controlling hyperglycemia.