List of lieutenant governors of Wisconsin
| Party | Lt. Governors |
| Republican | 29 |
| Democratic | 15 |
| Progressive | 2 |
The lieutenant governor is the first person in the order of succession of Wisconsin's executive branch, thus serving as governor in the event of the death, resignation, removal, impeachment, absence from the state, or incapacity due to illness of the Governor of Wisconsin.
Until 1979, the Wisconsin Constitution merely stated that in any of these events, "the powers and duties of the office shall devolve upon the lieutenant governor". Lieutenant governors who served as governor during this period are referred to as "acting governors". In 1979, the constitution was amended to make this more specific: in the event of the governor's death, resignation, or removal from office, the lieutenant governor becomes governor; in the event of the governor's impeachment, absence, or incapacity, the lieutenant governor becomes acting governor until the governor is again able to serve.
Under the original terms of the state constitution, the lieutenant governor was elected for a two-year term on a separate ticket from the governor; because of this, the Governor and Lieutenant Governor of Wisconsin have not always been of the same party. After a 1967 amendment, however, the two have been nominated, and voted upon, as a single ticket. Another 1967 amendment increased the terms of both the governor and lieutenant governor to four years. There is no limit to the number of terms a lieutenant governor may hold.
The original constitution made no provision for a vacancy in the office of the lieutenant governor; in the event of the lieutenant governor's death or resignation, the lieutenant governorship usually remained vacant until the end of the term. In 1938, following the resignation of lieutenant governor Henry Gunderson, Governor Philip La Follette appointed Herman Ekern lieutenant governor to fill the vacancy. This appointment was challenged in court, and ruled valid in the case State ex rel. Martin v. Ekern. In 1979 the constitution was amended to explicitly allow this: in the event of a vacancy in the office of the lieutenant governor, the governor nominates a candidate who becomes lieutenant governor for the remainder of the term upon his approval by the Wisconsin Assembly and Wisconsin State Senate.
Forty-one individuals have held the office of lieutenant governor since Wisconsin's admission to the Union in 1848, two of whom—Warren Knowles and Jack Olson—have served for non-consecutive terms. The first lieutenant governor was John Holmes, who took office on June 7, 1848. The current lieutenant governor is Mandela Barnes, who took office on January 7, 2019.
List of lieutenant governors
From 1836, until 1848, what is now Wisconsin was part of Wisconsin Territory. There was no position of "Territorial Lieutenant Governor"; however, the territory had a Secretary who was similar in that one of his functions was to assume the powers and duties of the territorial governor if he were unable to carry them out. For the secretaries from the territorial period, see the List of Secretaries of Wisconsin Territory.Wisconsin was admitted to the Union on May 29, 1848. Since then, it has had 41 lieutenant governors, two of whom have served non-consecutive terms.
;Parties
, 5th lieutenant governor of Wisconsin
, 8th lieutenant governor of Wisconsin
, 10th lieutenant governor of Wisconsin
Living former Lieutenant Governors of Wisconsin
, six former lieutenant governors are alive, the oldest being Margaret Farrow. The most recent death of a former lieutenant governor was that of Patrick Lucey, on May 10, 2014. The most recently serving lieutenant governor to die was Russell Olson on April 14, 2010.| Lt. Governor | Lt. Gubernatorial term | Date of birth |
| Martin J. Schreiber | 1971-1977 | |
| James T. Flynn | 1983-1987 | |
| Scott McCallum | 1987-2001 | |
| Margaret Farrow | 2001-2003 | |
| Barbara Lawton | 2003-2011 | |
| Rebecca Kleefisch | 2011-2019 |
Other high offices held
This is a table of governorships, congressional seats and other federal offices, and ranking diplomatic positions in foreign countries held by former Wisconsin lieutenant governors.| Name | Term | Other offices held |
| James Lewis | 1854-1856 | Governor of Wisconsin |
| Arthur MacArthur, Sr. | 1856 | Acting Governor of Wisconsin; Justice of the Supreme Court of the District of Columbia |
| Edward Salomon | 1862 | Acting Governor of Wisconsin |
| Thaddeus Pound | 1870-1872 | Representative from Wisconsin |
| James Davidson | 1903-1906 | Acting Governor of Wisconsin; Governor of Wisconsin |
| Walter Goodland | 1939-1943 | Acting Governor of Wisconsin; Governor of Wisconsin |
| Oscar Rennebohm | 1945-1947 | Acting Governor of Wisconsin; Governor of Wisconsin |
| Warren Knowles | 1955-1959 1961-1963 | Governor of Wisconsin |
| Jack Olson | 1963-1965 1967-1971 | Ambassador to the Bahamas |
| Patrick Lucey | 1965-1967 | Governor of Wisconsin; Ambassador to Mexico |
| Martin Schreiber | 1971-1977 | Acting Governor of Wisconsin |
| Scott McCallum | 1987-2001 | Governor of Wisconsin |