Jill Abbott is a fictional character from the American CBS soap opera The Young and the Restless. The longest-running and only remaining original character, Jill was created and introduced by William J. Bell. Originally portrayed by Brenda Dickson, when Dickson departed in 1980, the role was first recast with Deborah Adair. Dickson returned in 1983 and, although she stated that she would never leave the role again, she was replaced by Jess Walton in 1987, who continues in the role to present time.

When she debuted, Jill was an 18-year-old manicurist working to support her struggling family. The character is known for her rivalry with Katherine Chancellor (Jeanne Cooper), which is the longest feud in the history of American soap operas. Their rivalry began when she fell in love and slept with Katherine's husband Phillip Chancellor II (Donnelly Rhodes) and became pregnant. Following Phillip's accidental death, the women fought over custody of Jill's son, Phillip Chancellor III (Thom Bierdz), as well as numerous of Katherine's other husbands. A 2003 plot twist shockingly revealed Jill to be Katherine's long lost biological daughter, although in 2009, former head writer Maria Arena Bell rewrote their history, reversing that decision. In 2010, Jill discovered she is the daughter of Neil Fenmore (Jim Storm).

The character is considered an icon on the soap opera, and has been described as an integral part of the series. Both Dickson and Walton have characterized her as "manipulative". Walton, who classes her as a "savvy businesswoman", has opined she is similar to Gone with the Wind character Scarlett O'Hara. Critics have described her as both vindictive and a vixen. John Goudas of The Miami News said that the show "flourishes when her character takes center stage," while Nekeeta Borden of Zap2it noted that Jill has always craved a sense of belonging despite her personality. Walton's portrayal has been met with acclaim, having garnered her two Daytime Emmy Award wins.