Bark beetles (Coleoptera: Curculionidae; Scolytinae) are tree-infesting insects that consume subcortical tissues and fungi. Species capable of killing their host trees are most commonly associated with conifers, as very few bark beetle species infest and kill hardwood hosts directly. The alder bark beetle,Alniphagus aspericollis, is a hardwood-killing bark beetle that colonizes and kills red alder,Alnus rubra. Conifer-killing bark beetles have well-known associations with symbiotic ophiostomatoid fungi that facilitate their life histories, but it is unknown whetherA.aspericollishas any fungal associates. This study was conducted to identify any consistent filamentous fungal associates ofA.aspericollisand characterize the consistency of observed beetle–fungus relationships. Beetles and gallery phloem samples were collected from seven sites throughout the Greater Vancouver region in British Columbia, Canada. Filamentous fungi were isolated from these samples and identified by DNA barcoding using the internal transcribed spacer (ITS) region and other barcode regions for resolution to the species-level for the most dominant isolates. The most common fungal associate was a previously undescribedNeonectria major-like fungus,Neonectriasp. nov., which was isolated from ~67% of adult beetles, ~59% of phloem samples, and ~94% of the beetle-infested trees.Ophiostoma quercuswas isolated from ~28% of adult beetles, ~9% of phloem samples, and ~56% of infested trees and deemed a casual associate ofA.aspericollis, while a putatively novel species ofOphiostomawas more infrequently isolated fromA.aspericollisand its galleries.Cadophora spadicis, a new record for red alder, was rarely isolated and is probably coincidentally carried byA.aspericollis. Overall,A.aspericolliswas only loosely associated with ophiostomatoid fungi, suggesting that these fungi have little ecological significance in the beetle–tree interaction, whileNeonectriasp. nov. may be a symbiote ofA.aspericollisthat is vectored by the beetle.