Jill Tracy Jacobs Biden (born June 5, 1951) is an American educator and, as the wife of Vice President of the United States Joe Biden, is the Second Lady of the United States.

She was born in Hammonton, New Jersey and grew up in Willow Grove, Pennsylvania. She married Joe Biden in 1977, and became stepmother to his two young sons from his first marriage, Beau and Hunter, whose mother and baby sister died in a car accident. She and Biden had a daughter, Ashley, in 1981. Jill Biden has a bachelor's degree from the University of Delaware, master's degrees from West Chester University and Villanova University and a doctorate degree from the University of Delaware. She taught English and reading in high schools for 13 years, and also taught emotionally disturbed adolescents at a psychiatric hospital. From 1993 to 2008 she was an English and writing instructor at Delaware Technical & Community College. As of 2009, she is an adjunct professor of English at Northern Virginia Community College, and she is thought to be the first Second Lady to hold a paying job while her husband is Vice President.

She is the founder of the Biden Breast Health Initiative non-profit organization, co-founded the Book Buddies program, and is active in Delaware Boots on the Ground. She participated in her husband's presidential and vice-presidential campaigns while continuing her teaching responsibilities.