William Alexander Trapp (born January 15, 1993) is an American professional soccer player who plays as a midfielder for Inter Miami in Major League Soccer. He has appeared for the United States national team.
A native of Columbus, Ohio, Trapp graduated from Lincoln High School, where he was the 2010 NSCAA National High School Player of the Year, and played two years in college at Akron. He signed with Columbus Crew SC as a Homegrown Player, the fourth in club history, and would eventually be named as the club's captain. Trapp wore the armband for Crew SC for the first time on May 17, 2014, and received the nod permanently ahead of the 2017 season. While with Columbus, he was named as a 2016 MLS All-Star, and appeared in MLS Cup 2015.
At international level, Trapp first installed himself as a fixture for the United States with the youth teams. He captained the U20s at the 2013 FIFA U-20 World Cup, and did the same for the U23s in the 2016 CONCACAF–CONMEBOL play-off. Trapp earned his first cap for the senior national team on January 28, 2015.