Jimmy Donal Wales (born August 7, 1966), also known on Wikipedia by the pseudonym Jimbo, is an American-British Internet entrepreneur, webmaster, and former financial trader. He is a co-founder of the online non-profit encyclopedia Wikipedia and the for-profit wiki hosting service Fandom (formerly Wikia). He has worked on other online projects, including Bomis, Nupedia, WikiTribune, and WT Social.

Wales was born in Huntsville, Alabama, where he attended Randolph School, a university-preparatory school. He earned bachelor's and master's degrees in finance from Auburn University and the University of Alabama respectively. In graduate school, Wales taught at two universities; however, he departed before completing a PhD to take a job in finance and later worked as the research director of Chicago Options Associates.

In 1996, Wales and two partners founded Bomis, a web portal primarily known for featuring adult content. Bomis provided the initial funding for the free peer-reviewed encyclopedia Nupedia (2000–2003). On January 15, 2001, with Larry Sanger and others, Wales launched Wikipedia, a free open-content encyclopedia that enjoyed rapid growth and popularity. As its public profile grew, Wales became its promoter and spokesman. Though he is historically credited as a co-founder, he has disputed this, declaring himself the sole founder.

Wales serves on the Wikimedia Foundation Board of Trustees, the charity that he helped establish to operate Wikipedia, holding its board-appointed "community founder" seat. For his role in creating Wikipedia, the world's largest encyclopedia, Time named him one of "The 100 Most Influential People in the World" in 2006.