Youngest champions: since 2001
Youngest fighters to win an undisputed UFC title, by age on the day.
Reigns are derived from championship bouts. When a belt was vacated or stripped outside a title fight, the reign is shown ending at the next title fight in that division, so a few run long; a title awarded without a fight (José Aldo's in 2010, for one) starts at the champion's first UFC title fight.
102 fighters.
| # | Fighter | Age | Division | Won | Ended |
|---|---|---|---|---|---|
| 1 | Jon Jones | 23 years, 243 days | Light Heavyweight | Mar 19, 2011 | May 23, 2015 |
| 2 | Joshua Van | 24 years, 57 days | Flyweight | Dec 6, 2025 | Champion |
| 3 | Josh Barnett | 24 years, 132 days | Heavyweight | Mar 22, 2002 | Sep 27, 2002 |
| 4 | Jose Aldo | 24 years, 233 days | Featherweight | Apr 30, 2011 | Dec 12, 2015 |
| 5 | Carlos Newton | 24 years, 260 days | Welterweight | May 4, 2001 | Nov 2, 2001 |
| 6 | Frank Mir | 25 years, 26 days | Heavyweight | Jun 19, 2004 | Oct 7, 2005 |
| 7 | Ricco Rodriguez | 25 years, 39 days | Heavyweight | Sep 27, 2002 | Feb 28, 2003 |
| 8 | BJ Penn | 25 years, 49 days | Welterweight | Jan 31, 2004 | Oct 22, 2004 |
| 9 | Rose Namajunas | 25 years, 128 days | Women's Strawweight | Nov 4, 2017 | May 11, 2019 |
| 10 | Cody Garbrandt | 25 years, 176 days | Bantamweight | Dec 30, 2016 | Nov 4, 2017 |
| 11 | Max Holloway | 25 years, 181 days | Featherweight | Jun 3, 2017 | Dec 14, 2019 |
| 12 | Georges St-Pierre | 25 years, 183 days | Welterweight | Nov 18, 2006 | Apr 7, 2007 |
| 13 | Ronda Rousey | 26 years, 22 days | Women's Bantamweight | Feb 23, 2013 | Nov 14, 2015 |
| 14 | Demetrious Johnson | 26 years, 40 days | Flyweight | Sep 22, 2012 | Aug 4, 2018 |
| 15 | Jens Pulver | 26 years, 79 days | Lightweight | Feb 23, 2001 | Feb 28, 2003 |
| 16 | Dominick Cruz | 26 years, 115 days | Bantamweight | Jul 2, 2011 | Feb 1, 2014 |
| 17 | Anthony Pettis | 26 years, 216 days | Lightweight | Aug 31, 2013 | Mar 14, 2015 |
| 18 | Andrei Arlovski | 26 years, 245 days | Heavyweight | Oct 7, 2005 | Apr 15, 2006 |
| 19 | Vitor Belfort | 26 years, 305 days | Light Heavyweight | Jan 31, 2004 | Aug 21, 2004 |
| 20 | Tim Sylvia | 26 years, 360 days | Heavyweight | Feb 28, 2003 | Jun 19, 2004 |
| 21 | Renan Barao | 27 years, 1 day | Bantamweight | Feb 1, 2014 | May 24, 2014 |
| 22 | Ilia Topuria | 27 years, 27 days | Featherweight | Feb 17, 2024 | Apr 12, 2025 |
| 23 | Dave Menne | 27 years, 61 days | Middleweight | Sep 28, 2001 | Jan 11, 2002 |
| 24 | Carla Esparza | 27 years, 63 days | Women's Strawweight | Dec 12, 2014 | Mar 14, 2015 |
| =25 | Conor McGregor | 27 years, 151 days | Featherweight | Dec 12, 2015 | Jun 3, 2017 |
| =25 | Petr Yan | 27 years, 151 days | Bantamweight | Jul 11, 2020 | Mar 6, 2021 |
| 27 | Brandon Moreno | 27 years, 187 days | Flyweight | Jun 12, 2021 | Jan 22, 2022 |
| 28 | Joanna Jedrzejczyk | 27 years, 208 days | Women's Strawweight | Mar 14, 2015 | Nov 4, 2017 |
| 29 | Jessica Andrade | 27 years, 228 days | Women's Strawweight | May 11, 2019 | Aug 31, 2019 |
| 30 | Junior Dos Santos | 27 years, 286 days | Heavyweight | Nov 12, 2011 | Dec 29, 2012 |
| 31 | Matt Hughes | 28 years, 20 days | Welterweight | Nov 2, 2001 | Jan 31, 2004 |
| 32 | Amanda Nunes | 28 years, 40 days | Women's Bantamweight | Jul 9, 2016 | Dec 11, 2021 |
| 33 | Cain Velasquez | 28 years, 87 days | Heavyweight | Oct 23, 2010 | Nov 12, 2011 |
| 34 | Benson Henderson | 28 years, 101 days | Lightweight | Feb 25, 2012 | Aug 31, 2013 |
| 35 | TJ Dillashaw | 28 years, 106 days | Bantamweight | May 24, 2014 | Jan 17, 2016 |
| 36 | Mauricio Rua | 28 years, 164 days | Light Heavyweight | May 8, 2010 | Mar 19, 2011 |
| 37 | Frankie Edgar | 28 years, 176 days | Lightweight | Apr 10, 2010 | Feb 25, 2012 |
| 38 | Jack Della Maddalena | 28 years, 242 days | Welterweight | May 10, 2025 | Nov 15, 2025 |
| 39 | Sean O'Malley | 28 years, 299 days | Bantamweight | Aug 19, 2023 | Sep 14, 2024 |
| 40 | Quinton Jackson | 28 years, 340 days | Light Heavyweight | May 26, 2007 | Jul 5, 2008 |
| 41 | Nicco Montano | 28 years, 350 days | Women's Flyweight | Dec 1, 2017 | Dec 8, 2018 |
| 42 | Chris Weidman | 29 years, 19 days | Middleweight | Jul 6, 2013 | Dec 12, 2015 |
| 43 | Rashad Evans | 29 years, 93 days | Light Heavyweight | Dec 27, 2008 | May 23, 2009 |
| 44 | Forrest Griffin | 29 years, 111 days | Light Heavyweight | Jul 5, 2008 | Dec 27, 2008 |
| 45 | Khabib Nurmagomedov | 29 years, 199 days | Lightweight | Apr 7, 2018 | May 15, 2021 |
| 46 | Miesha Tate | 29 years, 200 days | Women's Bantamweight | Mar 5, 2016 | Jul 9, 2016 |
| 47 | Alexa Grasso | 29 years, 207 days | Women's Flyweight | Mar 4, 2023 | Sep 14, 2024 |
| 48 | Jiri Prochazka | 29 years, 240 days | Light Heavyweight | Jun 11, 2022 | Dec 10, 2022 |
| 49 | Natalia Silva | 29 years, 242 days | Women's Flyweight | Oct 3, 2026 | Champion |
| 50 | Dricus Du Plessis | 30 years, 6 days | Middleweight | Jan 20, 2024 | Aug 16, 2025 |