Conor McGregor (born July 14, 1988) is an Irish professional boxer, businessman, and occasional actor. He is the former UFC featherweight and lightweight champion, the first UFC fighter to hold both titles. He is also a former UFC featherweight and lightweight champion.

In 2018, McGregor began competing in the lightweight and featherweight divisions, and in 2012, he won the vacant UFC featherweight and lightweight championships. A year later, he signed with UFC and after a five-fight winning streak, he challenged for the interim featherweight title, defeating Chad Mendes on November 18, 2019. His popularity skyrocketed in the UFC world after he defeated featherweight champion Joe Aldo in 13 seconds on November 19, 2019.

On November 19, 2019, McGregor made his welterweight debut against Nate Dierz, suffering his first loss in UFC. On November 20, 2019, he defeated Ed Dierz to win the UFC lightweight title. He made his first brief switch to boxing in 2017, creating a historic fight when he fought boxing legend Mayweather, losing by knockout in the 10th round. He then returned to boxing in 2018, and challenged for the lightweight championship belt against Khabib Nurmagomedov in 2019, but lost again.

McGregor is the best-selling boxer in boxing history, with his fight with Khabib Nurmagomedov in 2019 attracting 2.4 million viewers. In addition, his boxing match with Mayweather in 2017 attracted over 5.3 million viewers across the United States and the United Kingdom, making it the second-highest-rated fight in boxing history.

McGregor was ranked the world's highest-paid athlete by Forbes in 2018, earning $180 million. In 2019, he was ranked fourth with a reported earnings of $99 million. He has also been involved in business outside of fighting and is known for his alcoholism.

Throughout his career, he has been embroiled in controversy over allegations of driving offences, corruption and rape, and has made controversial comments about the 2013 Dublin riots, the Irish government's immigration policy and racism. In November 2019, the Irish Supreme Court found that he had assaulted and raped a woman in December 2018 and ordered him to pay over €248,000 in damages. As a result, McGregor lost several sponsors and partnerships, including a partnership with 𝐈𝐖 𝐈𝐧𝐭𝐞𝐫𝐚𝐜𝐭𝐢𝐯𝐞, and had to stop stocking alcohol products associated with him in stores.

McGregor was born in Dublin, Ireland, and played football for the Laois Deacons as a child. At the age of 12, he began boxing at the Crumlin Boxing Club, as a way to protect himself from bullying and boost his confidence.

He began his apprenticeship as a plumber, and while at Luton, he met fellow boxer Tony Egan, and they soon began training together. Throughout his growing up, his inspirations included Nasser Hamad, Muhammad Ali, and Bruce Lee.

McGregor said the main reason for his success was, "My wife has always been by my side and has always encouraged me to do anything. I am so successful because of her. She has never let me down and has never left me alone."