Human beings are indwelled by a wide array of cellular microbes, building up their core microbiome. Amongst these, bacterial constituents comprise about 99% of the population. The remaining small, yet diverse population of microbes are termed the ‘rare-biosphere’. The eukaryotic yeasts contribute a substantial population within the rare biosphere. Despite the reduced abundance, yeasts/fungi cause a wide range of infections ranging from superficial to deep-seated, invasive, and life-threatening infections. This chapter provides an in-depth view of the role of fungi, specifically Candida albicans, in oral health and disease. We highlight the interactive profiles between the mycobiome and host oral tissues including study models for future state-of-the-art research in this important area.