Mycoplasma hominis is a strain of bacteria present in the vagina. It may or may not belong to the normal vaginal flora. It is also believed to be a cause of pelvic inflammatory disease. If so, it would be only one of many known causes.

This species is known to frequently colonise the genital tract of sexually active men and women. This bacterium has also been associated with post-abortal and post-partum fever.

Growth of a "fried egg" colonies on glucose agar medium within 24-48 hours is a characteristic of Mycoplasma hominins.