TfL will manage maintenance work on the Jubilee, Northern and Piccadilly lines from the end of next year when its current deal with Amey is terminated.
Amey has been working under the contract for the past 13 years under a legacy of the Public-Private Partnership (PPP) contract that previously existed between Tube Lines and London Underground.
The move is expected to save at least £80m over the next decade in management fees.
The Mayor of London, Sadiq Khan, said: “I’m really proud to announce that TfL will bring underground maintenance work back in-house.
“I’ve asked TfL to carry out a root-and-branch review of all its business operations, and the decision to bring underground maintenance work in-house will save tens of millions of pounds to invest in our transport network and pay for my freeze in TfL fares.
“London Underground already has experience running successful maintenance operations in-house, and we’re making the changes as soon as the contract allows. I want TfL to be the best in the world while staying in public control.”
Mark Wild, London Underground’s Managing Director, said: “We are carrying out a root-and-branch review of our business to cost less and make transport in London more affordable for our customers.
“As part of this, we are using our in-house maintenance expertise to save tens of millions of pounds.
“There will be no impact on our extremely high standards of maintenance and we will be working closely with Amey over the next 18 months to ensure a smooth transition.”