Jimmy Donal "Jimbo" Wales (pronounced /ˈdoʊnəl weɪlz/; born August 7, 1966) is an American Internet entrepreneur and a co-founder and promoter of Wikipedia.

Wales was born in Huntsville, Alabama. He attended a small private school, a university preparatory school, and then earned bachelor's and master's degrees in finance. While in graduate school, he taught at two universities. Wales later took a job in finance, and worked as the research director of a Chicago futures and options firm for several years. In 1996, he and two partners founded Bomis, a web portal that targeted males, and which hosted, and provided the initial funding for, the peer-reviewed encyclopedia Nupedia (2000 – 2003) and for its successor, Wikipedia.

In 2001, together with Larry Sanger and others, Wales helped launch Wikipedia, a free, open-content encyclopedia which subsequently enjoyed rapid growth and popularity. As Wikipedia's public profile grew, Wales became the project's promoter and spokesman. Wales has been historically cited as the co-founder of Wikipedia, though he has disputed that designation: Wales has said that he was the sole founder of the encyclopedia. He serves on the Board of Trustees of the Wikimedia Foundation, the non-profit charitable organization which operates Wikipedia. He holds its board-appointed "community founder" seat. In 2004, he co-founded Wikia, a privately-owned, free Web-hosting service, with fellow Wikimedia trustee Angela Beesley.