Zouma spent the 2017-18 campaign at Stoke City, where he was unable to stop the Potters dropping into the Championship.
"Kurt Zouma has joined Everton on loan until the end of the season," the club signalled on their official website.
"Frenchman Zouma moves from Chelsea and joins Brazil midfielder Bernard, Barcelona trio Yerry Mina, Andre Gomes and Lucas Digne, Richarlison and Joao Virginia in arriving at Goodison in the summer transfer window.
"After making his debut as a 16-year-old for Saint-Étienne in his homeland, Zouma established himself at the heart of their defence for three seasons before moving to Chelsea.
"Capped twice by France, he lifted the League Cup under Jose Mourinho in 2015."
New Toffees boss Marco Silva has been backed by hefty transfer investment in his first season on Merseyside, with Zouma his sixth major signing of the summer.
The Portuguese manager is tasked with improving on an eighth-place finish in the 2017-18 Premier League, with a return to European competition the objective for the Liverpool side.