Fungi represent an essential component of biodiversity, not only because of the large number of species, but also for their ecological, evolutionary and socio-economic significance. Yet, until recently, fungi received scant consideration in ecology, especially invasion ecology. Their under-representation is largely the result of a lack of scientific knowledge of fungal biodiversity and ecology. With the exception of pathogenic fungi, which cause emergent infectious diseases, the impact of fungal invasions is often difficult to quantify owing to limited baseline data on fungal communities. Here, we aim to raise awareness among mycologists and ecologists of the fungal dimension of invasions and of the need to intensify research in fungal ecology to address issues of future introductions.