The former Leicester City and Chelsea boss temporarily takes over from Ivan Juric, who was sacked from his post over the weekend in the wake of their 3-2 home loss to Bologna, which left them 12th in the Serie A table.
Ranieri becomes the fourth man to take charge of the Giallorossi in 2024 after Juric, Daniele de Rossi and Jose Mourinho, and he returns for a third spell in the Roma dugout after a first stint from September 2009 to February 2011 and another short spell in 2019.
After the 2024-25 season has finished, Roma have confirmed that Ranieri will remain at the club in the role of an advisor, where he will have an input on whom the Giallorossi appoint as their new permanent boss from 2025-26 and beyond.
"AS Roma is pleased to announce that Claudio Ranieri is the new Head Coach of the First Team," a statement on Roma's official website read.
"At the conclusion of the season, Claudio will transition into a senior executive role, where he will be an adviser to the ownership on all sporting matters at the club. The search for a future coach will proceed over the next months. Claudio will have input in that decision as well.
"The Club extends its best wishes to him for this exciting new chapter in his career, confident that he will be an invaluable asset to the team and to all of AS Roma. Forza Roma and welcome home, Mister!"
How did Ranieri do in his previous spells at Roma?
First taking charge of Roma in the early weeks of the 2009-10 season, replacing Luciano Spalletti, Ranieri led the Giallorossi to the Coppa Italia final that year - where they lost to Mourinho's Inter Milan - and a second-placed finish in Serie A.
Roma were just two points behind champions Inter at the conclusion of that campaign, but Ranieri then left his post midway through the 2010-11 season after a run of four straight defeats.
After his Premier League title miracle with Leicester City in the 2015-16 campaign, Ranieri returned to Stadio Olimpico for the latter stage of the 2018-19 campaign, where Roma went unbeaten in their last nine games of the Serie A season under his tenure.
Since last managing the Giallorossi, the 73-year-old has spent time in the hotseats of Sampdoria, Watford and Cagliari, and he previously announced his intentions to retire at the end of the 2023-24 season after finishing his spell with Cagliari.
However, the Italian will now look to steady the Roma ship after a rocky start to the season, and his first game in charge comes away to Serie A leaders Napoli on November 24, four days before a trip to Tottenham Hotspur in the Europa League.