AFC Asian Cup
The Oman Football Association announced Dutchman Verbeek's decision on its social media channels late on Wednesday.
Assistant coach Muhanna Said will be the stand-in coach until a suitable candidate is found, added the Oman FA.
Verbeek, who assumed the post in 2016, guided Oman to the Round of 16 of the AFC Asian Cup UAE 2019 with the spirited West Asians falling 2-0 to eventual semi-finalists Islamic Republic of Iran.
It was, however, a successful campaign as Oman had never previously advanced past the group stage in the Continental showpiece.
Verbeek, 62, also guided Oman to the 2017-18 Gulf Cup title, where they edged the United Arab Emirates on penalties in the final.