The fifteenth and final series of the British television music competition The X Factor began airing on ITV on 1 September 2018, presented by Dermot O'Leary. Simon Cowell returned alongside new judges Louis Tomlinson, Ayda Field (credited as Ayda Williams), and Robbie Williams who replace departing judges Nicole Scherzinger, Sharon Osbourne, and Louis Walsh. Nile Rodgers filled in for Williams while he was away on his tour for weeks 3–5 of the live shows.

On 2 December, Jamaican-born singer Dalton Harris won the series making him the first and only foreign contender to win the UK show. This was the only series that featured Tomlinson, Field, and Williams as judges.

After this series, the show was put on a 'break' and in 2019 the show was replaced by a Celebrity spin-off and a Band spin-off. In 2020, it was announced that the show was still on a 'break'. However, in July 2021, it was confirmed that the show has been officially cancelled after 17 years.

Judges and Presenters

On 6 June 2018, it was announced that Sharon Osbourne would return to judge the fifteenth series, but only for the live shows, due to her ongoing work commitments in the United States. The next day, long-serving judge Louis Walsh announced that after thirteen years on the show, he would leave to focus on other projects. Earlier in the year, it was reported that Nicole Scherzinger would not return as a judge for the fifteenth series.

On 30 September 2018, Osbourne announced her decision to no longer appear as a judge during the live shows, stating that she had "seen the new judges finding their rhythm and are doing brilliantly".

Simon Cowell confirmed his return as head judge and Dermot O'Leary’s return as presenter. After much speculation, it was announced on 16 July 2018 that Ayda Field (credited as Ayda Williams), Robbie Williams and Louis Tomlinson would join Cowell on the series' judging panel to replace Osbourne, Walsh, and Scherzinger respectively. On 17 October 2018, British DJ Jonas Blue confirmed that he auditioned for a judge position and was ready to take part in the series until prior gig commitments caused a clash in scheduling. He was later replaced by Tomlinson.

On 23 August 2018, it was announced that Xtra Bites would return after a first series, presented by Becca Dudley again, and she would be joined by a co-host named Tinea Taylor.

On 2 November 2018, it was revealed that Nile Rodgers would fill in for Williams on the panel during some of the live shows, due to Williams' touring commitments. Rodgers sat alongside Williams on 3 November, before fully substituting for him on 4, 10, 11 & 17 November. In a statement, Rodgers stated: "I had such a great time with Louis at the Judge's House in Ibiza a couple of weeks ago that when the opportunity came to step in for Robbie I could not say ('no')", "From Chic and Sister Sledge to Duran Duran and Daft Punk, I've had great experiences with Groups in my career, so I look forward to giving them as much support as I can while Rob is away!". Williams returned to the panel on 24 November.

Selection process

Auditions Auditions for performers took place only at London's SSE Arena, Wembley, on 18–20, 22–24 and 26–28 July 2018.

Deliberations Instead of the traditional bootcamp stages, a deliberation stage (similar to that employed by Britain's Got Talent) was introduced to cut down the number of performers at the six-chair challenge. This took place on 30 July 2018 at the Tobacco Dock in London. It was broadcast on a single episode on 23 September 2018 after the final auditions show.

After the "deliberation" and "reveal" stages, but before the start of the "six-chair challenge", the judges found out the categories they are mentoring: Tomlinson mentored the "Boys", Cowell mentored the "Girls", Field mentored the "Over 29s", and Williams mentored the "Groups".

Six Chair Challenge The Six Chair Challenge took place over the course of three days, from 1–3 August 2018, at the SSE Arena in Wembley. A new twist was added with the introduction of a golden button, similar to Got Talents Golden Buzzer. When this was pressed, the act in question was guaranteed a 'Safe Seat', and would go straight through to Judges' Houses. The Six Chair Challenge was aired over 3 episodes starting on 29 September 2018 and finished on 6 October 2018.

During this stage of the competition, Williams called back five soloists from the Boys category who had been rejected during the deliberations, and asked them to form a new five-piece boyband, Vibe 5 (later renamed United Vibe after judges' houses). After two American singers, Panda Ross and Burgundy Williams, had lost their seats after auditioning for Field's Overs category, Williams called them back to reaudition as a duo in the Groups category.

Judges' Houses It was announced by O'Leary during an appearance on This Morning that the Judges' Houses would be filmed in late September 2018, Tomlinson's houses would be hosted in Ibiza; and that three of the judges' houses would be in Los Angeles (Cowell, Field and Williams). Cowell judged from Malibu, while Field and Williams each judged their categories separately from their home in Beverly Hills. The guest judges were announced to be including Cowell's American Idol colleagues Paula Abdul, Randy Jackson and Ryan Seacrest along with Diane Warren, Babyface, Tomlinson was assisted by his One Direction bandmate Liam Payne and Nile Rodgers, Series 3 winner Leona Lewis and Sinitta to assist Cowell, who hosted a house party consisting of various singers, songwriters and record producers for the Girls to perform in front of. American Idol season 8 runner-up Adam Lambert and Lewis in assisting Field, and David Walliams with Williams.

Maria Laroco was not able to secure the correct visa in time to travel to Malibu with the remaining Girls for this stage of the competition. Unlike similar instances where the affected contestants withdrew from the competition, Laroco sang to Cowell via video link from a London studio. 16 contestants were put through to the live shows at this stage, four from each category. This last-minute change was lobbied by Cowell who was unable to narrow his Girls down to just three; the other judges were then allowed one more act each for their own categories as well.

+Summary of Judges' Houses Judge Category Location Assistants Acts Eliminated Cowell Girls Malibu Paula Abdul, Randy Jackson, Ryan Seacrest, Diane Warren, Babyface, Michelle Visage, Adam Lambert, Leona Lewis, Sinitta, Paul Anka, Tricky Stewart and Dallas Austin Georgia Burgess, Maria Laroco Field Over 29s Beverly Hills Adam Lambert and Leona Lewis Ricky John, Louise Setara Tomlinson Boys Ibiza Liam Payne and Nile Rodgers J-Sol, Thomas Pound Williams Groups Beverly Hills David Walliams Panda and Burgandy, Sweet Sense

Acts

Key: – Winner – Runner-Up – Golden Buzzer/Safe Seat (Six-Chair Challenge)

ActAge(s)HometownCategory (mentor)ResultDalton Harris24Clarendon, JamaicaBoys (Tomlinson)WinnerScarlett Lee21SurreyGirls (Cowell)Runner-UpAnthony Russell28BootleBoys (Tomlinson)3rd PlaceAcacia & Aaliyah 15 & 14LeylandGroups (Williams)4th PlaceBrendan Murray 21Tuam, Republic of IrelandBoys (Tomlinson)5th PlaceDanny Tetley36WiganOver 29s (Field)6th PlaceShan Ako25CroydonGirls (Cowell)7th PlaceBella Penfold 19Essex8th PlaceGiovanni Spano33West LondonOver 29s (Field)9th PlaceMisunderstood25 & 27LondonGroups (Williams)10th PlaceMolly Scott16County DurhamGirls (Cowell)11th PlaceUnited Vibe17–20VariousGroups (Williams)12th PlaceLMA Choir19–40Liverpool13th PlaceJanice Robinson50Galveston, Texas, United StatesOver 29s (Field)14th PlaceArmstrong Martins23Lagos, Nigeria/LondonBoys (Tomlinson)15th PlaceOlatunji Yearwood32Port of Spain, Trinidad and TobagoOver 29s (Field)16th Place

Live shows The contestants were announced after each category performed at Judges' Houses. There were 16 contestants (4 from each category) this year. The Live Shows were broadcast for 7 weeks from 20 October to 2 December. This year the live shows reverted to the previous format of all performances on the Saturday night and the results show on the Sunday night. However, there are 16 contestants and a reduced number of live shows, so almost all of the live result shows had double eliminations.

Nile Rodgers temporarily replaced Williams on the panel, due to touring commitments. Rodgers appeared in Williams's place from 4–18 November. For the first time since 2008, there was no elimination on the Saturday (1 December 2018). Instead, all top 3 contestants progressed the Sunday (2 December 2018) live final results show.

Musical guests Keala Settle and Rak-Su, the winners of the previous series, performed on the first live results show. Little Mix and Kylie Minogue performed on the second live results show. James Arthur and Jonas Blue, Liam Payne and Lennon Stella performed on the third live results show. Michael Bublé, Olly Murs and Lady Leshurr performed on the fourth live results show. Cheryl and Tom Walker performed on the fifth live results show. Benny Andersson and Björn Ulvaeus appeared on the sixth live show (Andersson doing a Masterclass with the semi-finalists and Ulvaeus appearing on the judging panel alongside Williams, Field, Tomlinson and Cowell to judge the performances). Zara Larsson performed on the sixth live results show.

The live final featured a performance from Robbie Williams (with Take That) on the live final results show.

Final venue Unlike the previous series where the live final was held at The ExCeL Center in London, instead this year's final was held at the normal venue which is The SSE Arena, Wembley in London.

Winners single The winners single was the winning contestant's duet from the Sunday (2 December 2018) result show with all proceeds going to the children's charities Together for Short Lives and Shooting Star Chase. It is the eighth year running that the Chancellor of the Exchequer has waived any VAT on The X Factor's winners single. The winner was announced to be Dalton Harris who performed a duet with James Arthur on "The Power of Love".

Results summary

Colour key Act in Boys

Act in Girls

Act in Over 29s

Act in Groups  –Act was in the bottom two/three and had to perform again in the sing-off –Act was in the bottom three but received the fewest votes and was immediately eliminated –Act received the fewest public votes and was immediately eliminated (no sing-off) –Act received the most public votes