The midfielder is a popular figure at Borussia Park having risen through the youth ranks with the Bundesliga club.
Herrmann made his debut as an 18-year-old in January 2010 and has gone on to make 185 appearances, scoring 35 goals.
"I love it here - it's great fun to play at Borussia and I feel the confidence of the association," he told the club's official website. "I feel at home here."
Sporting director Max Eberl added: "We are very pleased that we were able to bind Patrick to a new contract and that he wants to continue the successful path we have taken together.
"Patrick has developed from a young player and we are happy that he wants to make the next step in his career with us."
Herrmann has been a pivotal figure in a Gladbach side challenging for a UEFA Champions League berth this season, making 24 Bundesliga appearances and scoring eight goals.
