Johnson has started nine games for the Chiefs this season
Exeter Chiefs pair Tom Johnson and Haydn Thomas have agreed new deals at Sandy Park.
Flanker Johnson, 28, has signed a two-year extension to his contract, while scrum-half Thomas, also 28, has added a further three years to his deal.
Head coach Rob Baxter said: "This is very positive news for the club that we have already got players prepared to commit over the long term.
"Both Tom and Hadyn have played a big part in what we have done this season."
Baxter added: "It is decisions like this that demonstrate players want to buy into what we are trying to achieve here.
"I'm delighted that both the guys are willing to be part of what we want to achieve in the long term."