In April 1983, Koeman debuted for the Netherlands national team in a 3–0 friendly loss to Sweden in Utrecht.
This match also marked the first Oranje appearance for his elder brother Erwin.
Ronald's first international goal came in September of the same year, in a 3–0 victory of Iceland at Groningen's Oosterpark Stadion.

With the Netherlands unable to qualify for UEFA Euro 1984 and the 1986 FIFA World Cup, Koeman's tournament debut came at Euro 1988 in West Germany, where Rinus Michels' team defeated the hosts at the semi-final stage, with Koeman scoring a crucial penalty to equalize and make it 1–1.
After this match, Koeman provocatively pretended to wipe his backside with the shirt of Olaf Thon in front of the home supporters.

In the final, the Netherlands defeated the Soviet Union 2–0 at Munich's Olympiastadion to win the nation's only major international trophy.
This completed Koeman's extraordinary 1988 after winning the treble with PSV.
Both Koeman and his central defensive partner Frank Rijkaard were named in UEFA's Team of the Tournament.

Koeman went on to represent his nation at the 1990 and 1994 World Cups, as well as Euro 1992, and picked up a total of 78 caps for the Netherlands, scoring 14 goals.
In April 1983, Koeman debuted for the Netherlands national team in a 3–0 friendly loss to Sweden in Utrecht. This match also marked the first Oranje appearance for his elder brother Erwin. Ronald's first international goal came in September of the same year, in a 3–0 victory of Iceland at Groningen's Oosterpark Stadion.
With the Netherlands unable to qualify for UEFA Euro 1984 and the 1986 FIFA World Cup, Koeman's tournament debut came at Euro 1988 in West Germany, where Rinus Michels' team defeated the hosts at the semi-final stage, with Koeman scoring a crucial penalty to equalize and make it 1–1. After this match, Koeman provocatively pretended to wipe his backside with the shirt of Olaf Thon in front of the home supporters.
In the final, the Netherlands defeated the Soviet Union 2–0 at Munich's Olympiastadion to win the nation's only major international trophy. This completed Koeman's extraordinary 1988 after winning the treble with PSV. Both Koeman and his central defensive partner Frank Rijkaard were named in UEFA's Team of the Tournament.
Koeman went on to represent his nation at the 1990 and 1994 World Cups, as well as Euro 1992, and picked up a total of 78 caps for the Netherlands, scoring 14 goals.
Ronald Koeman