In the ancient Roman calendar, Quintilis or Quinctilis was the month following Junius (June) and preceding Sextilis (August).

After the calendar reform that produced a 12-month year, Quintilis became the seventh month, but retained its name. In 45 BC, Julius Caesar instituted a new calendar (the Julian calendar) that corrected astronomical discrepancies in the old. 

After his death in 44 BC, the month of Quintilis, his birth month, was renamed Julius in his honor, hence July.

Quintilis was under the guardianship (tutela) of the Romans’ supreme deity Jupiter, with sacrifices made particularly to Neptune and Apollo. The importance of agricultural festivals directed at the harvest gradually lost their importance, and the month became dominated in urban Imperial Rome by the Ludi Apollinares, games (ludi) in honor of Apollo.

According to the Roman calendar called the Gregorian calendar the month that belongs to Quintilis is July.

Ten days of games were celebrated in honor of Julius Caesar at the end of the month.