This is from wikipedia.
Juventus is the most well supported football club in Italy with over 11 million fans (31% of Italian football fans, according to the Doxa Institute-L'Expresso’s research of April 2006, and one of the most supported football clubs in the world, with approximately 21 million supporters in Europe alone. The Old Lady has fan clubs all over the world outside of Italy, from places as far apart as Malta, England,Iran,Greece,Israel,Vietnam,Hungary and many more.
Despite this strong support, attendances at Juventus home matches average about 35,000; much less than other highly renowned European teams. Contrastingly, demand for Juventus tickets in occasional home games held away from Turin is high; suggesting that Juventus have stronger support in other parts of the country.
Juve is widely and especially popular throughout Southern Italy, leading the team to have one of the largest followings in its away matches) than Turin itself. A large portion of Juventus fans in Turin do not attend the games and rather watch the games on TV, because of the conditions at Stadio delle Alpi; this is largely due to the running track which makes the pitch a long distance from the stands, work is ongoing to fix this problem.
Juventus ultras have good relationships with Piacenza, Ado Den Haag and Legia Warsaw fans and have several rivalries, two of which are highly significant.The first is with local club Torino, they compete in the Derby della Mole (Derby of Torino) together; this rivalry dates back to 1906 when Torino was founded by former Juve members.
The other most significant rivalry is with Internazionale; matches between Juventus and Inter are referred to as the Derby d'Italia (Derby of Italy). Up until the 2006 Serie A match-fixing scandal, which saw Juventus relegated, the two were the only Italian clubs to have never played below Serie A.
Notably the two sides are the most supported in Italy, the rivalry has intensified since the later part of the 1990s.
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This suggests that Juventus has more support outside Turin than in the city itself.Thats perplexing

.And i always thought Milan had the mosts fans in Italy after Juventus.