The school sponsors 32 varsity sports, most of which compete in the Division III New England Small College Athletic Conference (NESCAC).

The Ephs' nickname (which rhymes with "chiefs") is a shortened form of the name of Ephraim Williams, the college's founder.

[10] Williams has consistently won the NACDA Directors' Cup, an annual award for the most successful athletic program in each NCAA division.

[14] Varsity intercollegiate sports began at the school on July 1, 1859, when Williams was defeated by Amherst 73-32 in the first-ever college baseball game.

On May 3, 2009, Williams's baseball team played Amherst at Wahconah Park in Pittsfield, Massachusetts to commemorate the 150th anniversary of the 1859 game.

As a result, most of the college's 16 women's sports programs began varsity play during the 1970s,[18] with three exceptions (softball in 1987,[19] ice hockey in 1993,[20] and golf in 2004–2005[21]).

After defeating Rochester (NY) in the first round and Bates in the regional championship, the team advanced to the national quarterfinals against Wittenberg.

As a result of Wittenberg students' unruly celebrations after the game, Williams administrators decided to ban teams from participating in national tournaments.

[45] The team's home course is located near Mount Greylock High School in Williamstown, approximately five minutes from campus.

[50] As a NESCAC football team, the program is not permitted to play non-conference games or to participate in the NCAA Tournament.

[27] The program has had eight players, including one two-time selection, named to the Division III All-America Team since varsity competition began in 1903.

[27] Prior to the construction of Lansing Chapman in the 1950s, the team played outdoors on a pond near the current location of Cole Field, the Williams soccer facility.

[56] The program has had seven players, including one two-time and one three-time selection, named to the Division III All-America Team since varsity play began in 1902.

[59] The program has won the following honors:[60] The men's indoor track & field team is coached by David Thompson, who has held the position since the start of the 2013–2014 season.

[70] The program has won the following honors:[68] The men's outdoor track & field team is coached by David Thompson, who has held the position since the start of the 2014 season.

[73] The Nordic ski team competes at Prospect Mountain in Woodford, Vermont, approximately 30 minutes from campus.

The alpine ski team competes at Jiminy Peak in Hancock, Massachusetts, approximately 20 minutes from campus.

[76] The team has had 13 players go on to play professional and international soccer, including Mike Masters, Stephen Danbusky, Dan Calichman, Josh Bolton, Charlie Romero, and Khari Stephenson.

[14] As of the end of the 2013 season, the program has won eight consecutive national championships, a women's Division III record.

[45] The team's home course is located near Mount Greylock High School in Williamstown, approximately five minutes from campus.

In 2015, Ephs' Womens Golf won their first Team National Championship, led by sophomore, Sophie Kitchen, who finished third individually.

[27] The program has had three players named to the Division III All-America Team since the beginning of varsity play in the 1993–1994 season.

One of the program's All-Americans, Molly Wasserman, was a four-time selection (2001, 2002, 2003, 2004), who was also named the Division III National Player of the Year in 2004.

[73] The Nordic ski team competes at Prospect Mountain in Woodford, Vermont, approximately 30 minutes from campus.

The alpine ski team competes at Jiminy Peak in Hancock, Massachusetts, approximately 20 minutes from campus.

[27] The program has had numerous players named to the Division III All-America Team since varsity play began in the 1974–1975 season.

[179] In addition to Williams athletics, the rink has hosted the figure skating competition of the Winter Bay State Games.

[171] Samuelson-Muir Pool, part of the Chandler Athletic Complex, is the home of the men's and women's swimming & diving programs.

[171] Lasell Gymnasium, part of the Chandler Athletic Complex, is the home of the college's men's wrestling program.

If Williams wins its homecoming football game, played against either Amherst or Wesleyan, the team walks up Spring Street to St. Pierre's Barber Shop.