The following is a list of squads for each national team competing at the Euro 2012 in Poland and Ukraine. The tournament started on 8 June and the final took place in Kiev on 1 July 2012.
Each national team had to submit a squad of 23 players, three of whom must be goalkeepers, by 29 May 2012. If a player was injured severely enough to prevent his participation in the tournament before his team's first match, he could be replaced by another player.
Club memberships are correct as of 2011–12 season. Caps and goals correct as of 18 June 2012. Ages are correct as of 8 June 2012, the opening day of the tournament.
On 2 May 2012, Smuda named a provisional list of 26 players for the tournament, along with a seven-man reserve list. Łukasz Fabiański withdrew from the squad on 26 May 2012 with a shoulder injury and was replaced by Grzegorz Sandomierski from the reserve list; Smuda named his 23-man final squad the following day.
Santos named his first shortlist, composed of players based abroad, on 10 May 2012, and the second, composed of Greece-based players on 17 May 2012,. totalling a 25-player provisional list. On 28 May 2012, Santos announced his 23-man squad.
On 11 May 2012, Advocaat named a provisional list of 26 players for the tournament. Vasili Berezutski and Roman Shishkin withdrew on 20 and 24 May respectively, Berezutski with a thigh injury and Shishkin due to a stomach complaint. Advocaat named his final squad on 25 May 2012; Kirill Nababkin was named having not been included in the provisional party.
Michal Bílek announced his 24-man provisional squad on 14 May 2012. On 28 May 2012, he replaced Daniel Pudil with Vladimír Darida. The following day, he confirmed his 23-man squad, removing Tomáš Grigar.
On 7 May 2012, van Marwijk named a provisional list of 36 players for the tournament. However, Erik Pieters was forced to pull out of the squad shortly after the announcement with a foot injury. On 15 May 2012, van Marwijk reduced his squad to 27 players. On 26 May 2012, van Marwijk announced his 23-man squad for the tournament.
Vicente del Bosque named a squad to play in a set of warm-up matches on 15 May 2012, but it did not include any Barcelona, Athletic Bilbao, or Chelsea players as the two Spanish sides were preparing for the Copa del Rey final on 25 May, while Chelsea were to take on Bayern Munich in the Champions League final on 19 May. On 21 May 2012, del Bosque called-up Chelsea players Fernando Torres and Juan Mata for the friendly matches. On 27 May, del Bosque gave the final squad list, complete with Barcelona and Athletic Bilbao players.
On 7 May 2012, Giovanni Trapattoni announced his 23-man squad list for Euro 2012, along with a five-man stand-by list. Keith Fahey withdrew with a groin injury on 26 May and was replaced by Paul Green. On 29 May 2012 Kevin Foley was replaced by Paul McShane. The Ireland team was the only squad at the tournament to consist entirely of players from foreign leagues.
On 10 May 2012, a provisional list of 27 players was announced. On 29 May, the final 23-man squad was announced. On 4 June 2012, Ivica Olić was ruled out with an injury and was replaced by Nikola Kalinić. On 7 June 2012, Ivo Iličević was ruled out with an injury and was replaced by Šime Vrsaljko.
Roy Hodgson announced England's 23-man squad on 16 May 2012, along with a five-man stand-by list. The England team is the only squad to consist entirely of players from their domestic league. On 25 May, John Ruddy was ruled out with a broken finger; Jack Butland was called up as his replacement. On 28 May, Gareth Barry was ruled out with a groin injury, being replaced by Phil Jagielka. On 31 May, Frank Lampard was ruled out with a thigh injury and was replaced by Jordan Henderson. On 3 June, Gary Cahill was ruled out with a double fracture of his jaw and Martin Kelly was called up as his replacement.
Blanc named his first shortlist on 9 May 2012, consisting of 12 players playing abroad. On 15 May 2012 second shortlist of 15 France-based players was announced, while on the same day Tottenham defender Younès Kaboul was ruled out of the tournament with a knee injury, leaving Blanc with a 26-man squad. On 29 May 2012, Blanc announced his final 23-man squad.
The squads included five players who still had not made their debut at full international level prior to the start of the tournament. Of the five, only Giaccherini made his debut in the tournament. The five players were: