The election was necessitated by incumbent Republican Representative Ryan Zinke's appointment as United States Secretary of the Interior.

[2] Governor Steve Bullock declared a special election to take place on May 25, the earliest possible day he was legally allowed to choose.

The Green Party Convention on March 4, 2017, was held at the University of Montana's Payne Family Native American Center.

[54] The night before the election, Gianforte physically assaulted Ben Jacobs, a reporter from The Guardian, in front of multiple witnesses, knocking him down, punching him, and breaking his glasses.

Alicia Acuna, one of two Fox news reporters present, and the only eyewitnesses to the incident, stated that Jacobs had walked into the room, put a voice recorder up to Gianforte's face and began asking questions.