Juan Silveira dos Santos (Portuguese pronunciation: [ʒuˈɐ̃ siɫˈvejɾɐ dus ˈsɐ̃tus]; born 1 February 1979 in Rio de Janeiro), commonly known as Juan is a Brazilian footballer who currently plays as a central defender for Italian side Roma.

Juan played for six years for Flamengo in Brasil. In 2002, he moved to Bayer Leverkusen. He played five years in Germany scoring ten goals for Bayer. In 2007, he moved to Roma for €6.3 million.

Juan is currently playing for Roma. In all competitions for Roma he scored 11 goals in more than 140 appearances. With Roma he has won one Coppa Italia and Supercoppa Italiana. He has become a first-choice centre-back for Roma, and wears the number four jersey. Juan scored his first goal for Roma against Reggina on 16 September 2007.

In the 2011–12 season, he usually plays alongside Gabriel Heinze. He scored his seventh goal for Roma in a 5–1 win over Cesena on 21 January 2012. He scored again in Roma's 4–2 loss Cagliari in Sardinia, followed by his third goal of the season, and the opening goal, in Roma's 4–0 demolition of Internazionale at the Stadio Olimpico. Thus far he has scored nine goals for Roma.

Santos, originally Portuguese or Spanish for Saints (singular Santo), is a common surname in Spanish and Portuguese-speaking countries and the Philippines. Sometimes it can be the final part of a given name, generally preceded by the particle dos or de los (of the, meaning of the Saints, as in Miguel dos Santos, Michael of the Saints). It is a name associated with a great number of different people: