Silvius or Sylvius may refer to:
In fiction and mythology Alba Silvius, a Roman mythology king Aeneas Silvius, a mythological king Latinus Silvius, a mythological king Romulus Silvius, a mythological king Silvius (fictional character), a minor character in the pastoral comedy As You Like It Silvius (mythology), a king of Alba in Roman mythology Silvius Brabo, a mythical Roman soldier Tiberinus Silvius, a mythological king
People (real) Sylvius of Toulouse (4th century), Gallo-Roman bishop of Toulouse and saint Francis Sylvius (1581-1649), Flemish Catholic theologian Franciscus Sylvius (1614-1672), Dutch scientist and physician Jacobus Sylvius (1478–1555), French anatomist Johan Sylvius (1620–1695), Swedish painter Sylvius Leopold Weiss (1687–1750), German composer and lutenist Silvius Condpan (d. 2011), Indian National Congress politician Silvius Magnago (1914–2010), retired Italian politician
Other uses Silvius (fly), a genus of horsefly