Recent research focuses on exploring natural resources to improve the management of type 2 diabetes and to reduce the precarious health effects of synthetic drugs. This investigation aimed to appraise the antihyperglycemic potential of hydroalcoholic (70% ethanol) extracts of Inonotus pachyphloeus, Phellinus allardii, Ph. fastuosus, Ph. gilvus, Ph. sanfordii, and Ph. torulosus. Antihyperglycemic potential was screened using an in vitro inhibition of enzymatic starch digestion assay model. The amount of glucose liberation was determined using the 3,5-dinitrosalicylic acid method. Mushroom extracts showed a concentration-dependent inhibition of α-amyalse and α-glucosidase and a consequent decrease in glucose liberation. Extracts of Ph. fastuosus (half-maximal inhibitory concentration [IC50] = 27.33 ± 1.45 mg/mL) and Ph. sanfordii (IC50 = 30.33 ± 0.88 mg/mL) causing comparable inhibition of α-amyalse and α-glucosidase and decreased glucose liberation were evaluated in vivo through oral starch tolerance and oral glucose tolerance tests using Wistar albino rats. Acarbose (10 mg/kg body weight) was used as a positive control. The extracts of Ph. fastuosus and Ph. sanfordii (100, 200, and 400 mg/kg body weight) showed a dose-dependent decrease in blood glucose concentration, and this decrease was greater in starch-fed rats than in glucose-loaded rats. Ph. fastuosus and Ph. sanfordii extracts (200 and 400 mg/kg body weight) significantly reduced postprandial hyperglycemic peaks in rats challenged with excess starch and glucose. This decrease was statistically comparable to acarbose with Ph. fastuosus extract (400 mg/kg body weight). Thus, it may be concluded that the antihyperglycemic effect of Ph. fastuosus and Ph. sanfordii is mediated by inhibition of starch digestion (inhibition of α-amylase and α-glucosidase). Hence, Ph. fastuosus and Ph. sanfordii can be developed as natural antidiabetic drugs after detailed pharmacological studies.