The 2018 UK Championship (officially the 2018 Betway UK Championship) was a professional ranking snooker tournament, that took place from 27 November to 9 December 2018. It was the ninth ranking tournament and the first Triple Crown event of the 2018/2019 season. The event was broadcast on BBC Sport and Eurosport in the United Kingdom.
 Ronnie O'Sullivan, the defending champion, defeated Mark Allen 10–6 in the final, winning his 7th UK Championship and his 34th ranking event overall. In doing so, he became the first player since Stephen Hendry in 1996 to successfully defend the UK title. O'Sullivan broke Hendry's record for the most Triple Crown titles (18), Steve Davis's record of UK Championship titles (6) and became the second player to defend all Triple Crown tournaments at least once, after Hendry. The win was 25 years after his first UK Championship title as a 17 year old in 1993.
 Stuart Bingham made the event's highest break of 145 in the first frame of his third round match against David Gilbert.
 The total prize money for the event was identical to that of the previous year's event, with the winner earning £170,000 and an overall prize fund of £850,000. The breakdown of prize money and ranking points for this year is shown below:
 The "rolling 147 prize" for a maximum break stood at £15,000 but was not claimed.
 The 2018 UK Championship began on 27 November 2018. The tournament featured 128 players with no qualification round. All of the matches, up to and including the semi-finals, were played over a single session that was held as best of 11 frame matches, with the final played on 9 December over two sessions in a best of 19 frame match.
 The tournament opened on 27 November 2018 with the first round of 128 players, which saw a number of upsets: most notably twice champion and World number one, Mark Selby, fell to unseeded amateur James Cahill, 3–6; and former champion and ninth seed Shaun Murphy lost by the same scoreline to 120th seed Chen Feilong. Also, 12th seed Ryan Day lost 2–6 to 117th seed Joe O'Connor; 20th seed Anthony McGill lost 5–6 to 109th seed Lu Ning; and 102nd seed Sam Baird came from 1–5 down to beat 27th seed Liang Wenbo 6–5. Thrice champion and fourth seed John Higgins scraped past unseeded amateur Dechawat Poomjaeng 6–5, however, Higgins then lost in the second round 5–6 to Alan McManus.
 The televised portion of the event began on 1 December as the second round got underway. This round saw defending champion Ronnie O'Sullivan defeat Ken Doherty 6–5 despite being behind 1–4. Eighth seed Ding Junhui defeated Matthew Selt 6–5. 2018 Northern Ireland Open winner Judd Trump missed a black ball at the end of the tenth frame, which would have clinched a 6–4 win against Dominic Dale, but Trump then triumphed in the deciding frame, 6–5. James Cahill, who defeated world number one Mark Selby in the first round, lost to 64th seed Sunny Akani on another 5–6. Elsewhere in round two, Mark Williams and Barry Hawkins both recorded 6–0 whitewashes of their second round opponents, Daniel Wells and Ian Burns respectively. Hawkins' win was his second consecutive 6–0 win, having defeated his first round opponent Jamie Clarke by the same margin.
 The third round, played from 3 December 2018, saw the competition's last 32 players compete. The lowest ranked player remaining in the competition, Joe O'Connor (ranked 117th), was defeated by England's Joe Perry 2–6. However, 109th seed Lu Ning defeated 13th seed Luca Brecel 6–4. Ronnie O'Sullivan defeated Zhou Yuelong in a whitewash 6–0 to progress to the last 16.
 The fourth round began on 5 December 2018. Defending champion Ronnie O'Sullivan progressed to the quarter-finals, defeating Jack Lisowski by a 6–1 scoreline. However, world champion Mark Williams lost to 15th seed Stephen Maguire in a deciding frame, having led 4–0 earlier in the match. Martin O'Donnell (ranked 56th) upset China's eighth seed Ding Junhui by 6–4, and then defeated Judd Trump by the same scoreline to eliminate him from the competition. Tom Ford survived a decider with Lu Ning, the lowest ranked player left in the tournament. Meanwhile, Mark Allen also survived a deciding frame against Neil Robertson to go through to the quarter-finals, after making two consecutive centuries from 4–5 down.
 The event's quarter-finals began on 7 December 2018. The afternoon session saw defending champion O'Sullivan defeat Martin O'Donnell 6–1. This was O'Donnell's first Triple Crown quarter-final. Prior to the 2018/19 season, he had only reached the semi-finals of the 2018 Snooker Shoot Out. World number 21 Joe Perry was defeated by Tom Ford 2–6. This was Ford's first Triple Crown semi-final, and his third semi-final appearance since the 2013 Players Championship. He was runner-up in the 2016 Paul Hunter Classic.
 The second set of quarter-finals took place in the evening and saw Mark Allen defeat Stephen Maguire 6–1. Maguire blamed his loss on the playing conditions, stating that "you can't play good snooker" on the table used. Despite the scoreline, Allen said he felt as though "he didn't play well". In the last quarter-final, 2015 world champion Stuart Bingham defeated Kyren Wilson 6–2. During the match, Bingham attempted a maximum break; he potted fifteen reds and blacks, before missing the yellow ball.
 The semi-finals were played once again as best of eleven frame matches on 8 December 2018. The first semi-final match saw Tom Ford play Ronnie O'Sullivan. Ford won the opening frame of the match, with a break of 68, but lost the remaining six frames of the match, finishing 1–6. O'Sullivan reached the final, his fourth in five years, having declined to enter the UK Championship in 2015. The second semi-final was between Stuart Bingham and Mark Allen. The match finished in favour of Allen, who won 6–5, despite Bingham being ahead 4–2.
 The final was played on 9 December 2018 as a best of 19 frames match, spread over two sessions. It was contested between 2011 UK Championship runner-up Mark Allen and 2017 champion Ronnie O'Sullivan. The first four frames of the final were shared, however, the remaining four frames of the first session were won by O'Sullivan, leaving him 6–2 ahead after the initial session. In the evening session, O'Sullivan won the first frame, before Allen scored the highest break of the final (105), and entered the interval at 4–8 behind. O'Sullivan won the next frame, leaving him one frame from winning the tournament. Allen responded to clinch the next two frames including an attempt at a maximum break, which failed. O'Sullivan compiled a break of 78 in the 16th frame to win the championship.
 On winning the event, O'Sullivan overtook the record for both the number of UK Championship wins held by Steve Davis (6), and the total number of Triple Crown events held by Stephen Hendry (18). O'Sullivan's 2018 win was his seventh UK Championship, and nineteenth Triple Crown championship win overall. Of his achievement, O'Sullivan commented, "It's amazing to beat my hero Stephen Hendry's record. He was the ultimate player. I've still got eight world titles to get, so I'm chasing that one," referring to Hendry's greater number of World Snooker Championship victories.
 A total of 137 century breaks were made by 61 players during the 2018 UK Championship.
 The event was sponsored by betting company Betway, sponsors of the UK Championship since 2015. The tournament's broadcasters were dependent on country, with the BBC and Eurosport broadcasting across the United Kingdom and Europe respectively. The event was broadcast in China by Superstars Online, and China Central Television. In Hong Kong, NowTV simulcasted the event with additional commentary.
 During the event, two players Yu Delu and Cao Yupeng, were found guilty of match fixing. World number 52, Yu, was banned for ten years and nine months for fixing five matches over a three-year period. Cao was banned from snooker for six years (with three-and-a-half years suspended) for fixing three matches. The chairman of the World Professional Billiards and Snooker Association, Jason Ferguson, expressed his disappointment, stating that the players involved "risk their careers and they will be caught". World champion Mark Williams has suggested that players found cheating "should get banned for life".
 Ronnie O'Sullivan, who is critical of the number of events on the calendar and the punishing tour schedule, said he was ready to start a "breakaway tour" which would be separate from the World Snooker Tour. He stated that he would ask "four or five unhappy players", including Stephen Hendry and John Higgins, to start a new "Champions League-style" tour. He also indicated that he would invite players that were banned from World Snooker, including Yu and Cao. O'Sullivan insisted that the breakaway tour would benefit everybody, including the bottom-ranked players, but that his plan was a "last resort".
 In response, World Snooker chairman, Barry Hearn called the plan "nonsensical", and "damaging" to the sport. Hearn also fielded criticism of the current tour schedule from players of all levels, including world champion Mark Williams, Stephen Maguire and Neil Robertson.
 During the final, a draw was made for the 2019 Masters in January. The event would see first round matches between Mark Allen and Luca Brecel, and between Ronnie O'Sullivan and Stuart Bingham. Six weeks later, the 2019 Masters was won by Judd Trump, who defeated Ronnie O'Sullivan in the final on 20 January 2019.
 The next event of the season, the 2018 Scottish Open, began on 10 December, the day after the final of the UK Championship. O'Sullivan pulled out of the event hours after winning the UK Championship before his first round match with Daniel Wells. Having been given a bye through the first round, Wells  reached his first ranking event semi-final, building a 4–0 lead against Mark Allen, before eventually losing 5–6. Although O'Sullivan was not a competitor, he attended the Scottish Open to work on Eurosport's coverage of the event.
 Allen, after being runner-up at the UK Championship, won the Scottish Open despite stating that he had "disrespected" the tournament. He had consumed alcohol throughout the week, calling his appearance at the final "undeserved"; his highest break in the first four frames of his semi-final was just 24.