The 2015 mid-year rugby union internationals (also known as the Summer Internationals in the Northern Hemisphere) refer to international rugby union matches that were mostly played in the Southern Hemisphere during the June International Window.
As part of the World Rugby Global rugby calendar (2012–19), 2015 saw the first Rugby World Cup take place during the calendar. This meant, because of the 2015 Rugby World Cup, no test series', or June International Window, took place between the touring Northern Hemisphere nations and the Southern Hemisphere nations. This allowed the ordinary European season to finish 2 weeks later, due to the final of the 2014–15 Top 14 season taking place on 13 June. While the 2015 Super Rugby season was able to run for 21 consecutive weeks, with out the 3 week international break in June, to allow an earlier and shortened 2015 Rugby Championship.
Although the International Window did not take place, some World Cup nations opted to play uncapped matches that will go towards their World Cup preparations. England played their annual Twickenham fixture against the Barbarians, who also played Ireland for the first time since 2012. Uruguay hosted Fijian A-side, the Fiji Warriors in Montevideo, with the Warriors playing Argentina's A-side Argentina Jaguars, between the 2 fixtures. In addition to this, Argentina hosted the French Barbarians across 2 week-ends, repeating the same two fixtures they played in June 2011 before the 2011 Rugby World Cup. South Africa also played an invitational side, hosting a World XV side for second consecutive year. With Russia not competing in the 2015 Rugby World Cup, or either of World Rugby's Nations Cup or Tbilisi Cup, Russia toured Namibia for a two test-series.