There were 5,807 state legislative seats up for election on November 5, 2024, in 44 states. Across those elections, 303 incumbents lost their re-election bids: 134 in general elections and 169 in primaries. This was the second even-year election in a row that primary defeats outnumbered those in general elections.
Across primary elections in 2024, the 169 losses accounted for 3.5% of all incumbents who ran for re-election. The total number of incumbents defeated in primaries—169—was less than in 2022 (213) and more than in 2020 (157). The party breakdown for incumbents defeated in primary elections was:
- 34 Democratic incumbents lost, 1.5% of the 2,216 Democratic incumbents who ran.
- 135 Republican incumbents lost, 5.1% of the 2,626 Republican incumbents who ran.


In state legislative general elections, 134 incumbents lost to challengers, 2.9% of incumbents running for re-election. This was the lowest percentage of incumbents defeated in general elections since at least 2010. The 134 defeated incumbents represented a 40.0% decrease from the number of incumbents defeated in 2020. The party breakdown for incumbents defeated in primary elections was:
- 93 Democratic incumbents lost, 4.3% of the 2,176 Democratic incumbents who ran.
- 39 Republican incumbents lost, 1.6% of the 2,491 Republican incumbents who ran.
- Two minor party or independent incumbents lost, 18.2% of the 11 minor party or independent incumbents who ran.

