Holland has penned a new deal to 2026, extending his previous contract by two years.
The attacker joined Brentford two years ago from Sheffield Wednesday and is a member of the B squad.
“I’m really happy for Isaac to get his new deal. It’s been a process with Isaac to get to this point. This season he has been a mainstay in the team and performing at a high level consistently," said B manager Neil MacFarlane to the club's website.
"In recent months, he has had so many assists from wide areas for us and has really good attributes that he has continued to develop.
“He has grown each year and you can see he is playing with a lot of confidence, which comes down to his work ethic.
“He has a bright future and hopefully this new contract will allow us to keep pushing him in the upward trajectory he currently finds himself in."