The bark beetle Ips typographus carries numerous fungi that could be assisting the beetle in colonizing live Norway spruce (Picea abies) trees. Phenolic defenses in spruce phloem are degraded by the beetle’s major tree-killing fungus Endoconidiophora polonica, but it is unknown if other beetle associates can also catabolize tree defenses. We compared the ability of five fungi commonly associated with I. typographus to degrade phenolic compounds in Norway spruce phloem. In addition to E. polonica, Grosmannia penicillata and G. europhioides were also able to degrade stilbenes and flavonoids and grow on minimal growth medium with spruce bark constituents as the only nutrients. Although beetles avoided medium amended with phenolics, they preferred medium colonized by E. polonica and O. bicolor with intermediate phenolic degradation ability, over medium colonized by the Grosmannia species, which had the highest degradation ability of the tested species, underlining the complexity of beetle-fungus interactions.