The Serie A powerhouse have named former Azzurri manager Spalletti to lead the team for the rest of the term.
Spalletti steps in for the Croatian manager, who was sacked following the loss to Lazio last weekend.
Tudor had joined the club in March to replace Thiago Motta but exited following a seven-month stint following a string of eight matches without a victory.
Spalletti guided Napoli to the Serie A crown in 2022-23 before taking charge of Italy, after the team's failure to reach the 2022 World Cup with Mancini at the helm.
He helped them qualify for Euro 2024 where they were knocked out in the last 16 by Switzerland.
However, Spalletti was sacked by Italy in June following a loss to Norway in World Cup qualifying, with the Azzurri at risk of missing out on a third consecutive World Cup.
He has previously coached Inter Milan, Roma, and Udinese in Italy's top flight and secured two Russian Premier League titles with Zenit St Petersburg.
Massimo Brambilla took interim charge of Juventus in the midweek 3-1 triumph over Udinese which left them seventh in Serie A - six points behind leaders Napoli after nine games.
In the Champions League, they sit 25th in the league phase, having lost once and drawn twice in their opening three matches.
