Wild mushrooms, while largely explored for their ecological significance, have not been systematically studied for their medicinal properties. This is the first report of biological activities of mushrooms from Haida Gwaii, British Columbia, Canada. The 17 mushroom species in this study were collected from multiple locations on Haida Gwaii and were screened for antiproliferative, immunostimulatory, and anti-inflammatory activities. Prior to screening, mushrooms were genetically identified and then sequentially fractionated into four crude extracts using 80% ethanol, 50% methanol, water, and 5% sodium hydroxide. We report here the strong antiproliferative and antiinflammatory activities of Amanita augusta, Phellodon atratus, Guepinia helvelloides, Chroogomphus tomentosus, Laetiporus conifericola, and Inocybe sp. In addition, A. augusta, G. helvelloides, and Inocybe sp. showed potent immunostimulatory activity. Two other species (Ganoderma tsugae and Pleurotus ostreatus) displayed strong immunostimulatory activity consistent with previous reports by others, suggesting that similar constituents are present in the same species from Haida Gwaii. For nine species (Russula paludosa, Hygrophoropsis aurantiaca, Tricholomopsis rutilans, Tyromyces chioneus, Hydnum repandum, Hypholoma fasciculare, Clavulina cinerea, P. ostreatus and Ramaria cystidiophora), we describe antiproliferative, immunostimulatory, and/or anti-inflammatory activities that have never been reported before. The new findings serve as a platform for future investigations into the potentially novel bioactive constituents of these mushrooms, as well as an incentive to further study a wider array of wild mushrooms for medicinal properties.