Anthony Lee Ervin (born May 26, 1981) is an American competitive swimmer who has won four Olympic medals and two World Championship golds. At the 2000 Summer Olympics, he won a gold medal in the men's 50-meter freestyle, and earned a silver medal as a member of the second-place United States relay team in the 4×100-meter freestyle event. He was the second swimmer of African descent, after Anthony Nesty of Suriname, to win an individual gold medal in Olympic swimming. He is the first United States citizen of African descent to earn a gold medal in an individual Olympic swimming event. In 2017, he knelt for the US national anthem prior to the start of a competition in Brazil.

Ervin stopped swimming competitively at the age of 22 in 2003 and auctioned off his 2000 Olympic gold medal on eBay to aid survivors of the 2004 tsunami, but he began to train again in 2011.

Ervin competed in the 50-meter freestyle event at the 2012 Summer Olympics where he placed fifth. In the spring of 2016, Akashic Books released Ervin's memoir, Chasing Water, co-authored by Ervin and Constantine Markides. At the 2016 Summer Olympics, 16 years after his first Olympic gold medal, he won the event for the second time, at the age of 35, becoming the oldest individual Olympic gold medal winner in swimming.

Ervin is African-American and Jewish, and was born in Hollywood. He is of Ashkenazi Jewish descent on his mother's side and African-American and Indian-American descent on his father's. He was raised in Valencia, Santa Clarita, California. Ervin has described himself as a "Zen Buddhist". He practiced Zen meditation. In July 2017 he said: "I'm proud to be American and I'm proud to be a Jew."

While living in Santa Clarita, he swam for Canyons Aquatic Club, and also competed on Hart High School's swim team. Anthony enrolled and swam for the University of California, Berkeley, under Hall of Fame Head Coach Nort Thornton Jr., receiving his bachelor's degree in English in 2010. Ervin also received coaching from Berkeley Head Coach Dave Durden.

He has pursued a graduate degree in sport, culture and education at Berkeley.

As a youth, Ervin had tics that he described "as an itch that constantly [wanted] to be scratched"; as a young adult he would attract negative attention for the symptoms. He attributes his success in the pool to his Tourette syndrome. He states that swimming helped him manage his facial tics when he was young and the condition made him learn how to cope with anxiety from an early age, which benefitted him when he was in the Olympic finals. Ervin was a youth ambassador for the Tourette Association of America from 2017 to 2018.

At the 2000 United States Olympic Trials in Indianapolis, Ervin competed in two events: the 50-meter and 100-meter freestyle. In the finals of the 100-meter freestyle, Ervin finished fifth with a time of 49.29, ensuring him a spot on the 4×100-meter freestyle relay. In the final of the 50-meter freestyle, Ervin finished second to Gary Hall Jr. with a time of 21.80.