The 23-year-old’s previous deal had been due to expire at the end of next season, but he has agreed a new contract which leaves the club with the option of extending for a further year beyond that.
Smith has made 43 appearances this season for the Terriers and 70 in total since moving from Manchester City in the summer of 2012.
Huddersfield manager Chris Powell told the club’s official website: “Tommy has established himself as an important member of our first-team squad and a regular starter both at right-back and also within a back three.
“He is still a relative novice in terms of professional experience in a tough division, but he has played a lot of Championship games in a short period of time since his debut, which is testament to his ability, fitness and development. Tommy deserves a lot of credit for that.”