A vaginal cyst is a closed sac on or under the vaginal lining that contains fluid or semisolid material.

There are several types of vaginal cysts, which can range in size from the size of a pea to that of an orange. Vaginal inclusion cysts are the most common. These may form as a result of trauma sustained by the vaginal walls or following an obstetric or gynecologic procedure, when the lining of the vagina doesn't heal to its normal smoothness.

Gartner's duct cysts develop in the space occupied by the Gartner's duct, usually on the side walls of the vagina. This duct is active during fetal development but ordinarily disappears after birth. In some cases, however, portions of the duct may collect fluid and develop into a vaginal wall cyst later in life.

Benign tumors of the vagina are uncommon and are usually made up of cysts.