Human skin microbiota has been studied intensively for over 10 years. Several important findings have been made, but also gaps in knowledge are wide. The structure and interaction of microbiota and skin immunity has been shown to be significant in many skin conditions. Interaction depends on skin site, age, overall health and anatomical location in skin area. Of particular importance are antimicrobial peptides. Microbiota acts as natural adjuvant in skin and aids innate responses. Skin-infiltrating T lymphocytes interact directly with cutaneous microbiota. An emerging area is the effect of commensals on immune imprinting early in life, with unconventional T cells and dendritic cells playing a key role. Interactions with the host during bacterial, fungal and viral infections have been shown. Other areas include effects on maturation of mast cells, skin barrier and wound healing, as well as neoplastic transformation.