Quagliarella played for the Italian youth sides, known as the Azzurrini, from the 2000–01 season up until the 2004–05 season. He made his debut for the Italy U17 team (equivalent to the current Italy U18 side) on 5 September 2000 against Slovakia. The following season, he was a member of the Italy U19 team during their 2002 UEFA European Under-19 Championship qualifying campaign. Following his impressive performances with Sampdoria in the 2006–07 season, Quagliarella was called up to the Italian senior squad, known as the Azzurri, for a friendly against Romania in February 2007. However, his senior international debut was delayed, as the match was cancelled as a result of fan riots in Serie A that weekend. Quagliarella finally made his senior debut for Italy on 28 March 2007, in a Euro 2008 qualifier against Scotland in Bari, coming on as a substitute for Luca Toni in the final minutes of the 2–0 win. In Kaunas on 6 June 2007, he made his first start for Italy in a vital Euro 2008 qualifier against Lithuania, also scoring his first two goals for the national side in the eventual 2–0 win. On 6 February 2008, he scored his third goal for Italy, and his nation’s third goal of the match, in their 3–1 triumph over Portugal in an international friendly in Zurich; this was also the 1200th goal scored by the Italian national side. Quagliarella was subsequently included in the Italian UEFA Euro 2008 squad by manager Roberto Donadoni; he made his only appearance of the tournament in Italy’s second group match, a 1–1 draw against Romania, coming on as a second half substitute for Alessandro Del Piero. Italy then bowed out of the tournament on penalties to eventual champions Spain in the quarter-finals. Quagliarella was subsequently called up to Italy’s 23-man squad for the 2009 FIFA Confederations Cup in South Africa under returning manager Marcello Lippi; his only appearance throughout the tournament came in Italy’s second group match, a 1–0 defeat to Egypt. Italy were disappointingly eliminated from the tournament in the group stage following a 3–0 defeat to eventual champions Brazil in their final group match. Quagliarella was also included in the final 23-man Italian 2010 FIFA World Cup squad by coach Marcello Lippi; on 5 June 2010, he scored a header in a 1–1 away draw against Switzerland in Italy’s final friendly before the tournament. In Italy’s final match of Group F at the 2010 World Cup against Slovakia, Quagliarella came on at the beginning of the second half for Gennaro Gattuso, with Italy trailing 1–0, and in the space of 45 minutes, he contributed to teammate Antonio Di Natale’s goal, who scored from a rebound, and subsequently executed a beautiful 25-yard chip in injury time to bring the score to 3–2; furthermore, throughout the match, he also had a volley cleared off the line by Slovak defender Martin Škrtel, and had an equalising goal controversially ruled offside, although he was ultimately unable to prevent the Italians from losing 3–2, resulting in one of Italy’s most shocking World Cup eliminations. The match was his 21st cap for Italy, while his goal was his seventh overall. Although the Italian team was widely criticised in the media, Quagliarella was praised for his performance. Under Italy’s new manager Cesare Prandelli, Quagliarella scored Italy’s fourth goal in a 5–0 home win in a Euro 2012 qualifying match against the Faroe Islands on 7 September 2010. He later also appeared in a friendly against Romania held in Klagenfurt on 17 November, scoring the equalising goal in the 1–1 draw; although some sources cite Italy’s goal as an own goal, the Italian Football Federation recognises the goal as Quagliarella’s. On 2 September 2014, Quagliarella was recalled to the national team for a friendly match against the Netherlands and UEFA Euro 2016 qualifying matches against Azerbaijan and Norway under new Italy manager Antonio Conte, although he did not appear during the matches. On 3 October 2015, Quagliarella earned his most recent call-up, once again for Italy’s Euro 2016 qualifying matches against Azerbaijan and Norway; once again, he did not appear during the matches.