<p>Ergosterol, a key component of fungal cell membranes, plays a central role in plant-fungi interactions. Structurally analogous to cholesterol in animal cells, it stabilizes fungal membranes, influencing fluidity and permeability. This unique sterol has evolutionary significance, marking a distinct separation between fungal and plant lineages, and has been pivotal in fungal adaptation to diverse ecological niches. Ergosterol acts as a signalling molecule in plant-fungi associations, impacting the establishment of symbiotic relationships. From a physiological perspective, ergosterol is critical for modulating plant responses such as photosynthesis or altering mitochondrial membrane fluidity. However, research on the effects of ergosterol on other aspects of plant physiology remains underlooked, highlighting a significant gap. Moreover, ergosterol biosynthesis is targeted by antifungal compounds, underscoring its importance in the development of fungal biocontrol strategies. The specialized role of ergosterol in fungal physiology and its association with plants is dynamic for plant-fungal relationship. This review highlights the potential role of ergosterol in plant-fungal interactions.</p>