2018 Acadia Senate elections

Elections were held on September 1, 2018 to fill all 495 seats of the Senate of Acadia. This coincided with the elections for the president and the fifth seat on the Supreme Court.

Results
The center-right Conservative Party, which had held a majority in the Senate since 2014, lost 142 seats. The center-left Social Democrats won a majority. All other parties experienced an increase, except for the Communist Party which retained its sole seat.

Ideological divisions
The composition of the Senate elected in 2018 consists of: two left-wing parties, two center-left parties, two right-leaning centrist parties, one center-right party, and one right-wing party.

Prime Minister election
To qualify for the Prime Minister election on October 15, 2018, candidates must be an incumbent senator and have the exclusive support of at least 10 other senators. Every party with representation in the Senate nominated their leader, excluding the National Party and Peace League (neither enough had 10 supporting senators).

Senators were given a paper ballot listing the six candidates in alphabetical order. Senators were required to rank all six in order of preference. After five rounds of tabulation, Social Democrat nominee James Wren defeated Conservative Gerald Coleman, 247-221. He was sworn-in by the Dean of the Senate later that day.