The attacking midfielder joins from Championship side Norwich City.
Huddersfield Town have completed the signing of Norwich City midfielder Alex Pritchard.
The 24-year-old has signed a three and a half year contract - with the option for the Terriers to add a further year.
The former Tottenham Hotspur attacking midfielder will wear the number 21 shirt.
He's previously been named in the PFA's Championship Team of the Year, as well as representing England at Under-21 level.
Huddersfield Town Head Coach David Wagner said: "I'm very happy to be able to welcome Alex to Huddersfield Town.
"He is exactly the type of player that we like to work with at this Club. Alex is a young, British player who arrives as one of the top performers in the Sky Bet Championship and with a desire to prove himself in the Premier League.
"Now we will work hard with him to give him every possibility of being a success for us in the top division.
"I'd like to thank Dean Hoyle and the Board for being as supportive as ever in this transfer window and making this transfer possible."