The Ultimate Fighting Championship introduced two weight classes at UFC 12: Heavyweight, which grouped competitors above 200 lb (91 kg), and Lightweight, which grouped competitors under 200 lb.
The UFC gradually introduced various weight classes and the promotion currently consists of 12 different weight classes, with the initial division being Strawweight and the highest-ranked division being Heavyweight.
| Weight Class Name | Minimum Weight | Upper Weight Limit | Current Champion |
| Women's Strawweight | 106lb (48 kg ; 7.5 st) | 115 lb (52.2 kg; 8.2 st) | Zhang Weili |
| Flyweight | 115 lb (52.2 kg; 8.2 st) | 125 lb (56.7 kg; 8.9 st) | Deiveson Figueiredo |
| Bantamweight | 125 lb (56.7 kg; 8.9 st) | 135 lb (61.2 kg; 9.6 st) | Petr Yan |
| Featherweight | 135 lb (61.2 kg; 9.6 st) | 145 lb (65.8 kg; 10.4 st) | Alexander Volkanovski |
| Lightweight | 145 lb (65.8 kg; 10.4 st) | 155 lb (70.3 kg; 11.1 st) | Khabib Nurmagomedov |
| Welterweight | 155 lb (70.3 kg; 11.1 st) | 170 lb (77.1 kg; 12.1 st) | Kamaru Usman |
| Middleweight | 170 lb (77.1 kg; 12.1 st) | 185 lb (83.9 kg; 13.2 st) | Israel Adesanya |
| Light Heavyweight | 185 lb (83.9 kg; 13.2 st) | 205 lb (93.0 kg; 14.6 st) | Jan Błachowicz |
| Heavyweight | 205 lb (93.0 kg; 14.6 st) | 265 lb (120.2 kg; 18.9 st) | Stipe Miocic |
| Women’s Flyweight | 115 lb (52.2 kg; 8.2 st) | 125 lb (56.7 kg; 8.9 st) | Valentina Shevchenko |
| Women’s Bantamweight | 125 lb (56.7 kg; 8.9 st) | 135 lb (61.2 kg; 9.6 st) | Amanda Nunes |
| Women’s Featherweight | 135 lb (61.2 kg; 9.6 st) | 145 lb (65.8 kg; 10.4 st) | Amanda Nunes |
| Rank | Fighter | Weight Class | Win/Loss Record |
| 1 | Khabib Nurmagomedov | Lightweight (2008–2010, 2012–2020) Welterweight (2009–2011) | 29-0 |
| 2 | Jon Jones | Light Heavyweight(2008-2020), Heavyweight (2021-) | 26-1,1NC |
| 3 | Israel Adesanya | Middleweight | 20-0 |
| 4 | Kamaru Usman | Welterweight | 18-1 |
| 5 | Stipe Miocic | Heavyweight | 20-3 |
| 6 | Alexander Volkanovski | Featherweight (2014–present) Lightweight (2014; 2016) Welterweight (2012–2013) | 22-1 |
| 7 | Dustin Poirier | Lightweight (2009–2010, 2015–present) Featherweight (2011–2014) | 27-6, 1NC |
| 8 | Max Holloway | Featherweight (2012–present) Lightweight (2010–2011, 2019) | 22-6 |
| 9 | Deiveson Figueiredo | Flyweight | 20-1-1 |
| 10 | Petr Yan | Bantamweight | 15-1 |
| 11 | Justin Gaethje | Lightweight | 22-3 |
| 12 | Robert Whittaker | Welterweight (2009-2014). Middleweight (2014-present) | 22-5 |
| 13 | Francis Ngannou | Heavyweight | 15-3 |
| 14 | Jan Blachowicz | Light Heavyweight | 27-8 |
| 15 | Conor McGregor | Featherweight (2008–2015) Lightweight (2008–2012, 2016–2018, 2021-present) Welterweight (2016, 2020) | 22-5 |
| Rankings | Fighter | Win/Loss record |
| 1 | Brandon Moreno | 18–5–2. |
| 2 | Joseph Benavidez | 28-7 |
| 3 | Askar Askarov | 12-0-1 |
| 4 | Alex Perez | 24-6 |
| 5 | Alexandre Pantoja | 23-5 |
| Ranking | Fighter | Win/Loss record |
| 1 | Aljamain Sterling | 19-3 |
| 2 | Cory Sandhagen | 14-2 |
| 3 | Rob Font | 18-4 |
| 4 | Cody Garbrandt | 12-3 |
| 5 | Jose Aldo | 29-7 |
| Rankings | Fighters | Win/Loss record |
| 1 | Max Holloway | 22–6 |
| 2 | Brian Ortega | 15–1 (1 NC) |
| 3 | Zabit Magomedshapirov | 18-1 |
| 4 | Yair Rodriguez | 13-2, 1 NC |
| 5 | Chan Sung Jung | 16-6 |
| Rankings | Fighter | Win/Loss Record |
| 1 | Dustin Poirier | 27-6, 1 NC |
| 2 | Justin Gaethje | 22-3 |
| 3 | Charles Oliveira | 30-8, 1NC |
| 4 | Michael Chandler | 22-5 |
| 5 | Tony Ferguson | 26-5 |
| Rankings | Fighter | Win/Loss record |
| 1 | Colby Covington | 16-2 |
| 2 | Gilbert Burns | 19-4 |
| 3 | Leon Edwards | 18-3 |
| 4 | Jorge Masvidal | 35-14 |
| 5 | Stephen Thompson | 16-4-1. |
| Rankings | Fighter | Win/Loss record |
| 1 | Robert Whittaker | 22–5 |
| 2 | Paulo Costa | 13–1 |
| 3 | Jared Cannonier | 13–5 |
| 4 | Darren Till | 18–3–1 |
| 5 | Marvin Vettori | 16-4-1. |
| Rankings | Fighter | Win/Loss record |
| 1 | Glover Teixeira | 32–7 |
| 2 | Thiago Santos | 21–8 |
| 3 | Dominick Reyes | 12–2 |
| 4 | Aleksandar Rakić | 13–2 |
| 5 | Jiří Procházka | 27–3–1 |
| Rankings | Fighter | Win/Loss record |
| 1 | Francis Ngannou | 15–3 |
| 2 | Derrick Lewis | 25-7 (1 NC) |
| 3 | Curtis Blaydes | 14-3, 1 NC |
| 4 | Ciryl Gane | 8-0 |
| 5 | Alexander Volkov | 33-8 |
| Rank | Fighter | Weight Class | Win/Loss Record |
| 1 | Amanda Nunes | Bantamweight (2011–present), Featherweight (2008–2011, 2018–present) | 20-4 |
| 2 | Valentina Shevchenko | Bantamweight (2003–2005, 2010–2017), Flyweight (2006, 2018–present) | 20-3 |
| 3 | Weili Zhang | Strawweight | 21-1 |
| 4 | Rose Namajunas | Strawweight | 9-4 |
| 5 | Jessica Andrade | Bantamweight (135 lbs) (2011–2015) Strawweight (115 lbs) (2016–2020) Flyweight (125 lbs) (2020–present) | 21-8 |
| 6 | Joanna Jedrzejczyk | Flyweight (2012–2014, 2018–present), Strawweight (2014–2018, 2019–present) | 16-4 |
| 7 | Germaine De Randamie | Bantamweight (2008-2011, 2013-16, 2018-Present), Featherweight ( 2011-12, 2017) | 10-4 |
| 8 | Holly Holm | Bantamweight (2011-2016, 2017, 2019), Featherweight (2017-2018) | 14-5 |
| 9 | Aspen Ladd | Flyweight (2015), Bantamweight (2016-present) | 9-1 |
| 10 | Katlyn Chookagian | Strawweight (2014), Flyweight (2014-2016, 2018-Present), Bantamweight (2016-17). | 15-4 |
| 11 | Nina Ansaroff | Strawweight (2010-2013, 2014-Present), Flyweight (2013-Present) | 10-6 |
| 12 | Yan Xiaonan | Atomweight, Strawweight | 13-1, 1 NC |
| 13 | Carla Esparza | Strawweight | 9-2-1. |
| 14 | Cynthia Calvillo | Flyweight (2016, 2020-present), Strawweight (2017-2019) | 18-5 |
| 15 | Claudia Gadelha | Strawweight | 18-6 |
| Rankings | Fighter | Win/Loss record |
| 1 | Rose Namajunas | 9–4 |
| 2 | Joanna Jędrzejczyk | 16–4 |
| 3 | Yan Xiaonan | 13–1 (1 NC) |
| 4 | Carla Esparza | 17–6 |
| 5 | Nina Ansaroff | 10–6 |
| Rankings | Fighter | Win/Loss record |
| 1 | Jessica Andrade | 21-8 |
| 2 | Katlyn Chookagian | 15-4 |
| 3 | Lauren Murphy | 14-4 |
| 4 | Jennifer Maia | 18-7-1. |
| 5 | Cynthia Calvillo | 9-2-1. |
| Rankings | Fighter | Win/Loss Record |
| 1 | Germaine De Randamie | 10-4 |
| 2 | Holly Holm | 14-5 |
| 3 | Aspen Ladd | 9-1 |
| 4 | Irene Aldana | 12-6 |
| 5 | Yana Kunitskaya | 14-5, 1 NC |
No rankings available for UFC Women's Featherweight division.
Click here for the current UFC Rankings in detail as per respective Weight Classes.
