The ovary is an important organ in the female reproductive system which produces oocytes and female sex steroid hormones estrogen and progesterone. These hormones play an important role in female traits such as breast development, body shape, and body hair. They are also involved in the menstrual cycle, fertility, and pregnancy. The ovary progresses through many stages in the lifetime of a women beginning in the prenatal period, childhood, adolescence, and adulthood through menopause. This ICOG campus discusses several aspects related to the ovary. These include physiology of ovulation, ovarian reserve testing, polycystic ovarian syndrome, ovulation induction and its complications, role of adjuvants in ovulation induction and improving ovarian reserve, premature ovarian insufficiency, ovarian aging and its stages, and hormonal therapy.