The Berlin-born midfielder has just a single first-team appearance to his name in his fledgling career, after making a brief cameo for Leipzig in the second tier during the 2015-16 campaign.
Toure will initially join up with Juve's reserve team in Serie C, but should the former Germany Under-19 international impress in Italy, the Old Lady can take up their purchase option before his season-long loan expires.
"Idrissa should train regularly with the first team and get minutes for the second team," Werder sporting director Frank Baumann told the club's official website.
"It's a very good opportunity for him to develop at the highest level."
Juventus have already been busy bolstering their senior ranks this summer, with high-profile deals completed.
Five-time Ballon d'Or winner Cristiano Ronaldo has joined the Serie A champions from Real Madrid while experienced centre-half Leonardo Bonucci has returned to Turin from AC Milan.