Juniperus plant species are rich sources of bioactive secondary metabolites and are traditionally used for the treatment of several illnesses, including those related to hyperglycemia and diabetes. The major bioactive compounds identified in certain species of this genus are terpenes and phenolics. Juniperus deppeana Steud. is mainly used as a wood resource and its chemical composition has been partially established. Our goal was to perform a comprehensive profiling of a methanolic extract of leaves of J. deppeana, and to determine its potential as a source of α-amylase and α-glucosidase inhibitors. Terpene and phenolic compounds were putatively identified based on their accurate mass spectrometric data. Regarding terpenes, we found mainly diterpenes, specifically dehydroabietic acid-like, hinokiol-like, agathic acid-like and dihydroxyabietatrienoic acid-like compounds. Isopimaric acid was also identified and its identity was confirmed by coelution with an authentic standard via comparing retention time, mass spectrum, and collisional cross section (CCS) values. For phenolic compounds, we identified mainly compounds with a chemical structure similar to the biflavonoids amentoflavone and bilobetin. Besides, the methanolic extract of J. deppeana leaves show inhibition of α-amylase (IC50= 85.11 ± 11.91 µg mL-1) and α-glucosidase (IC50= 32.50 ± 3.40 µg mL-1) enzymes, demonstrating a potential alternative for the search of antidiabetic natural products.