The season began on 11 August 2017 and concluded on 28 April 2018, with the play-offs taking place in May 2018.
[4] On 28 April 2018, Crusaders won the title on the final day of the regular season, defeating Ballymena United 2–1 at the Ballymena Showgrounds to win the league title for the third time in four seasons.
Carrick Rangers finished second from bottom but retained their Premiership place after winning the promotion-relegation play-off against NIFL Championship promotion play-off winners Institute 5–2 on aggregate.
As a result, the four teams finishing 4th–7th took part in Europa League play-offs to decide which one team would qualify for the 2018–19 UEFA Europa League first qualifying round.
[9] However, as the third-placed Championship team, Harland and Wolff Welders did not apply for a Premiership licence, the second-placed team, Newry City advanced directly to the play-off.