The former Barcelona boss will take over from Louis van Gaal, who revealed recently on Dutch TV show Humberto he has undergone 25 rounds of radiation treatment for prostate cancer. The 70-year-old has continued to work and did not tell his players of his condition when the Netherlands squad got together in March for friendlies against Denmark and Germany.
However, Van Gaal will remain in charge for the tournament in Qatar, which takes place between November 21 and December 18, with Koeman resuming the role he left in 2020 after that.
The news was confirmed by the Royal Dutch Football Association (KNVB) on Wednesday.
"I am looking forward to the new collaboration," Koeman said. "A little over a year and a half ago, I certainly did not leave the Dutch national team out of dissatisfaction.