Randy Thorsteinson is an Alberta politician.

Thorsteinson graduated from Brigham Young University in 1980 with a major in business management. Following various business ventures he entered politics as an activist for the Reform Party of Canada in 1988. He joined the Alberta Social Credit Party in 1991 and became leader the following year.

Under Thorsteinson Social Credit experienced the beginnings of a rebirth, and in the 1997 general election the party nominated 70 candidates and collected almost seven per cent of the popular vote, but failed to elect any MLAs.

By 1999, however, Thorsteinson, a Mormon convert, was at odds with his party after the Social Credit executive moved to limit the involvement of the Latter Day Saints. Thorsteinson quit the party in April 1999 and would go on to form the Alberta Alliance, whose leadership he assumed in February 2003.

Thorsteinson's new party gained momentum immediately following the 2004 Canadian federal election when Edmonton—Norwood MLA Gary Masyk crossed the floor to join the Alberta Alliance. He was the Alberta Alliance's first MLA.

Later that year in the Alberta general election, 2004 Thorsteinson placed a distant second in votes in his riding of Innisfail—Sylvan Lake , failing to become a MLA. His party won one seat in the election; Paul Hinman was elected MLA for the riding of Cardston—Taber—Warner .

On March 7, 2005 Thorsteinson announced his resignation as leader of the Alberta Alliance, citing that he would not be able to devote the time and energy into the party. Paul Hinman, the lone MLA for the Alliance in the legislature, is mentioned as a possible candidate to succeed Thorsteinson.