New Hampshire state elections in 2018 were held on Tuesday, November 6, 2018, with the primary elections being held on June 5, 2018. Voters elected 2 members to the United States House of Representatives, the Governor of New Hampshire, all five members to the Executive Council, all 24 members to the New Hampshire Senate, and all 400 members to the New Hampshire House of Representatives, among other local elected offices.
The primary election was held on Tuesday, June 5, 2018.Turnout by county:
| Belknap County | 46,189 | 11,352 | 24.58% | |
| Carroll County | 37,233 | 11,274 | 30.28% | |
| Cheshire County | 57,022 | 12,641 | 22.17% | |
| Coos County | 20,094 | 4,599 | 22.89% | |
| Grafton County | 67,404 | 14,536 | 21.56% | |
| Hillsborough County | 270,722 | 63,357 | 23.40% | |
| Merrimack County | 109,163 | 28,302 | 25.93% | |
| Rockingham County | 234,112 | 54,722 | 23.37% | |
| Strafford County | 92,087 | 20,965 | 22.77% | |
| Sullivan County | 28,370 | 6,514 | 22.96% | |
| Totals | 962,396 | 228,262 | 23.72% |
The general election was held on Tuesday, November 6, 2018.Turnout by county:
| Belknap County | 47,856 | 27,229 | 56.90% | |
| Carroll County | 40,166 | 24,336 | 60.59% | |
| Cheshire County | 60,018 | 32,789 | 54.63% | |
| Coos County | 20,595 | 11,788 | 57.23% | |
| Grafton County | 71,748 | 40,758 | 56.81% | |
| Hillsborough County | 282,659 | 164,337 | 58.14% | |
| Merrimack County | 113,433 | 65,887 | 58.08% | |
| Rockingham County | 244,859 | 141,565 | 57.81% | |
| Strafford County | 98,529 | 54,072 | 54.88% | |
| Sullivan County | 29,141 | 17,453 | 59.89% | |
| Totals | 1,009,004 | 580,214 | 57.50% |
New Hampshire held no election for the United States Senate in 2018, as the state is not represented in the Senate by a seat of Class 1.
New Hampshire's two seats in the United States House of Representatives were up for election. Both seats were retained by the Democratic Party.
Incumbent Republican Chris Sununu was reelected against Democratic nominee Molly Kelly.
See main article: 2018 New Hampshire Executive Council election. All 5 seats of the New Hampshire Executive Council were up for election. Democrats were able to gain one seat and thus achieved a 3–2 majority.
See main article: 2018 New Hampshire Senate election. All 24 seats of the New Hampshire Senate were up for election. Democrats achieved a 14–10 majority.
See main article: 2018 New Hampshire House of Representatives election. All 400 seats of the New Hampshire House of Representatives were up for election. Democrats achieved a 234–166 majority.