| Election Name: | 1966 Maine gubernatorial election |
| Country: | Maine |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1962 Maine gubernatorial election |
| Previous Year: | 1962 |
| Next Election: | 1970 Maine gubernatorial election |
| Next Year: | 1970 |
| Election Date: | November 8, 1966 |
| Image1: | Photo SOS 026 Kenneth M Curtis.jpg |
| Nominee1: | Kenneth M. Curtis |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 172,036 |
| Percentage1: | 53.1% |
| Nominee2: | John H. Reed |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 151,802 |
| Percentage2: | 46.9% |
| Map Size: | 300px |
| Governor | |
| Before Election: | John H. Reed |
| Before Party: | Republican Party (United States) |
| After Election: | Kenneth M. Curtis |
| After Party: | Democratic Party (United States) |
The 1966 Maine gubernatorial election took place on November 8, 1966. Incumbent Republican Governor John Reed, had been elected to finish the term of Clinton Clauson in 1960, was then re-elected in 1962 and became the state's first four-year Governor. Reed was seeking a second full four-year term, and was challenged by Democrat Kenneth M. Curtis, having defeated James Erwin for the Republican nomination. Curtis defeated Reed, beginning a twenty-year period of Republican isolation from the Blaine House.
This was the last gubernatorial election in Maine in which a non-incumbent candidate won with a majority of the vote, until Janet Mills won with 50.8% of the vote in 2018. As of 2023, Reed is the most recent incumbent governor to lose re-election; all succeeding Governors have been re-elected, with the exception of James B. Longley, who did not run for re-election in 1978, holding himself to a one-term promise.