Jerry Francis Costello (born September 25, 1949), American politician, has been a Democratic member of the United States House of Representatives since 1988, representing Illinois's 12th congressional district (map), which includes the St. Louis area suburb cities and stretches to deep Southern Illinois. Costello was born in East St. Louis, Illinois and attended Catholic schools, graduating from Assumption High School. He was later educated at Maryville College of the Sacred Heart in St. Louis, from which he earned a bachelor's degree.

Costello worked in the law enforcement field. He served St. Clair County, Illinois as a court bailiff, deputy sheriff, and director of court services and probation. Costello later was chief investigator for the Illinois State Attorney’s office. In 1980, he was elected to the St. Clair County Board and was chosen as chairman. Costello served in this capacity as county executive until his election to the house. He earned a reputation as a fiscal moderate while serving on the Board and he took aim at balancing the county's budget. He also took interest and established a reputation for expertise in infrastructure and transportation issues. Costello led the move to bring "light rail" a mass transit train system to the St. Louis metropolitan area. He prevailed in having the first St. Louis area line established in Illinois and running to Lambert St. Louis International airport. Early skeptics later sided with Costello's vision in expanding the rail line to St. Louis City and St. Louis County. Today the St. Louis area "light rail system" is a resounding success and one of Costello's lasting legacies.

Costello took office on August 9, 1988 after winning a special election to fill the seat of the deceased Melvin Price. He was elected to a full term that November, and has been reelected to every succeeding Congress; currently he is the most senior member of Illinois' House delegation. In 2006, he ran unopposed for the office. Costello continues to spend most of his free time in his hometown instead of the Metro Washington area. He is known for holding town hall meetings and for his participation in political forums. He is also known for his strong constituent services. He was reelected easily in 2008.