"Last night I took the decision to end my stint as head coach of the Dutch National Team," Koeman said in a statement on Instagram.
"We all shared the dream of making history at this World Cup, but we fell short. No one is more disappointed by that than I am.
"As head coach, the responsibility ultimately rests with me."
The Netherlands had been tipped to make a run deep into the tournament but Morocco beat them 3-2 in a penalty shootout after the match in Monterrey had finished 1-1 at the end of extra time.
The Netherlands were leading 1–0 in the final minutes of the match thanks to a Cody Gakpo goal, but they conceded an equaliser deep in stoppage time when Issa Diop scored.
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World Cup 2026
The 2026 World Cup will be held from June 11th to July 19th in the United States, Canada and Mexico. The tournament will feature 48 national teams and will be played in 16 modern stadiums.
Match schedule and times | Knockout draw | Final group standings | England at the World Cup | Team rosters at the World Cup | How to watch the World Cup | Predictions and odds | Team of the Group Stage