Milan Mačvan

Even before getting the first-team action on the club level with FMP, Mačvan began playing international competitions for Serbian national youth teams.

In 2007, 17-year-old Mačvan had a busy and successful summer. First, in mid-July, he led the Serbian under-19 team to victory at the Under-19 World Cup in Novi Sad, earning the MVP honours in the process. In the final, Serbia defeated the United States team featuring Stephen Curry and DeAndre Jordan. Then, only ten days later, Mačvan was included by head coach Dejan Mijatović on the Serbian under-18 team, leading it to gold at the Under-18 European Championship in Madrid, with a team-best 19.3 points and 10.3 rebounds per game over 8 games. For his efforts, at the end of 2007, Mačvan received the Golden Badge Award as the Best Young Athlete of the Year in Serbia given by Sport newspaper.

In early August 2008, 18-year-old Mačvan played for the Serbian under-20 team at the 2008 FIBA Europe Under-20 Championship in Riga, Latvia. Coached by Slobodan Klipa, this time around, Mačvan's stats weren't as dominant as the duo of Miroslav Raduljica and Marko Kešelj took over the leading roles in the beginning stages of the tournament. However, as the matches progressed, Mačvan started regaining top form and made a huge contribution in the final versus Lithuania, leading the team with 31 points. He finished the tournament with 16.9 points and 6.6 rebounds per game over 8 games.

In late summer 2009, coming off a great club season at Hemofarm as well as helping Serbia win the 2009 Universiade tournament on home soil in early July, Mačvan made the Serbian national team 12-man roster head coach Dušan Ivković took to EuroBasket 2009 in Poland. Being on a young squad whose oldest members were 26-year-olds Bojan Popović and Nenad Krstić, 19-year-old Mačvan was the squad's youngest player. Despite the player's youth and inexperience at the big stage, coach Ivković gave Mačvan decent minutes off the bench at his major tournament debut game versus world champions, Olympic silver medalists, and EuroBasket runners-up Spain that Serbia surprisingly won 66-57 while Mačvan contributed with 8 points and 3 rebounds in 17 minutes of action, hitting two clutch three-pointers in the third quarter,[18] incidentally his only field goals of the contest. The group stage continued with a loss versus Slovenia and this time Mačvan got 18 minutes backing up Novica Veličković at the power forward position as his scoring output dropped off to 4 points. In the second group stage outings — wins against host Poland followed by a loss to Turkey — Mačvan's playing time decreased, before getting a slight bump versus Lithuania in the closing group stage contest while his scoring contribution became almost negligible. At the first single-elimination stage, quarterfinal win versus Russia, the youngster's game saw a slight boost with 5 points, though this was followed by a complete omission in the hard-fought semifinal overtime win versus Slovenia as Ivković preferred the more experienced Veličković. In the final the next day, tired and emotionally spent Serbian team lost big to Spain with young Mačvan getting little opportunity to play.

Mačvan played at the 2010 FIBA World Championship in Turkey, and at the EuroBasket 2011 in Lithuania.

In early July 2013, despite receiving a call-up for EuroBasket 2013, Mačvan didn't show up at the Serbian national team training camp.[19] Asked by the Serbian media about the reasons for Mačvan not being there, head coach Ivković said he didn't know them and revealed that the coaching staff's attempts to reach the player in order to see what's going on were unsuccessful.[19] As a result of Mačvan's failure to show up, Ivković decided to make two subsequent call-ups, to 20-year-old Nemanja Krstić and 21-year-old Nikola Kalinić[19] both of whom went on to make the final 12-man roster and make their competitive debuts for the national team.

In early June 2014, the national team's newly appointed head coach Saša Đorđević announced Mačvan alongside 28 other individuals on the preliminary list of players he was considering for the 12 final roster spots at the 2014 FIBA World Cup.[20] On 1 July, announcing the official call-ups for the start of the training camp, Đorđević crossed out 9 names from the preliminary list including Mačvan's, saying the 24-year-old got excluded for tactical reasons while adding he had "an unfocused season [at Galatasaray] without a specific position".[21] Two days later when Novica Veličković, one of the 20 players who received call-ups, announced he wouldn't be showing up to training camp due to knee injury, agitated Đorđević criticized him in the media: "I'm blindsided and disappointed by Veličković's unfair move. We've been in constant contact before the call-up list had been announced and not once did he mention anything about an injury... More than anything else he owes an explanation to Duško Savanović and Milan Mačvan, two players that weren't called-up because I gave Veličković the advantage over them. If you're wondering if I'll now be calling-up either Savanović or Mačvan, I won't be. My face is way too red in front of them over this to do that now".[22]

Mačvan represented Serbia at the 2016 Summer Olympics where they won the silver medal, after losing to the United States in the final game with 96–66.[23]

Mačvan also represented and captained Serbia at the EuroBasket 2017 where they won the silver medal, after losing in the final game to Slovenia.[24] Over 9 tournament games, he averaged 10.8 points, 4 rebounds and 2.7 assists per game.