Catherine Baker Knoll was an American politician and member of the Democratic Party. She was the 30th lieutenant governor of Pennsylvania, serving under Governor Ed Rendell from 2003 to 2008, when she died in office. Prior to that, she served as the 72nd Pennsylvania treasurer from 1989 to 1997. She was the first, and to date, the only woman to be lieutenant governor of Pennsylvania.

The lieutenant governor is a constitutional officer of the Commonwealth of Pennsylvania. The lieutenant governor is elected for a four-year term in the same year as the governor. Each party picks a candidate for lieutenant governor independently of the gubernatorial primary. The winners of the party primaries are then teamed together as a single ticket for the fall general election. The lieutenant governor presides in the Pennsylvania State Senate and is first in the line of succession to the governor; in the event the governor dies, resigns, or otherwise leaves office, the lieutenant governor becomes governor. The Lieutenant Governor casts tie breaking votes in the State Senate.