The 2024 New Hampshire Democratic presidential primary was held on January 23, 2024, as part of the Democratic Party primaries for the 2024 presidential election. The January New Hampshire primary was not sanctioned by the Democratic National Committee (DNC). The DNC-approved 2024 calendar placed the South Carolina primary first, but New Hampshire state law mandates them to hold the first primary in the country, and a "bipartisan group of state politicians", including the chairs of the Democratic and the Republican parties, announced that the state would preserve this status. Thus, the DNC initially stripped all 33 of the state's delegates that would have been allocated to the Democratic National Convention. The delegates will be allowed to be seated at the convention following the holding of a party-backed firehouse primary on April 27.

The New Hampshire presidential primary is the first in a series of nationwide party primary elections and the second party contest, the first being the Iowa caucuses, held in the United States every four years as part of the process of choosing the delegates to the Democratic and Republican national conventions which choose the party nominees for the presidential elections to be held in November. Although only a few delegates are chosen in the New Hampshire primary, its real importance comes from the massive media coverage it receives, along with the first caucus in Iowa.