Courtois will sign a six-year contract at the Bernabeu subject to agreeing personal terms and passing a medical.
Croatia international Mateo Kovacic will join the Blues on a season-long loan as part of the deal.
A statement released by Chelsea on Wednesday read: “Chelsea and Real Madrid have tonight agreed terms for the permanent transfer of Thibaut Courtois subject to the agreement of personal terms and passing a medical.
“Subject to the completion of the deal Mateo Kovacic will join the Blues on a season-long loan.”
Madrid confirmed Courtois will undergo his medical on Thursday before being unveiled to the club’s fans at the Bernabeu.
A statement read: “After the medical that will take place tomorrow, Thursday 9 August, the player will be presented at 1pm in the presidential box at the Santiago Bernabeu stadium.
“Subsequently, Courtois will go out on the pitch at the Santiago Bernabeu for the first time wearing the Real Madrid jersey and will speak to the media in the press room.”
Chelsea are expected to sign Athletic Bilbao goalkeeper Kepa Arrizabalaga as Courtois’ replacement at Stamford Bridge.
Bilbao announced on Wednesday that Kepa’s £71m buyout clause had been activated and his contract terminated – although there was no mention of Chelsea in the club’s official statement.
Such a fee would make the Spain international the most expensive goalkeeper in history, surpassing the £67m fee Liverpool paid to sign Alisson earlier this summer.