Commission chief Ursula von der Leyen responded to his notification by thanking Timmermans, 62, for his work leading the bloc’s ambitious Green Deal pact towards a carbon-neutral future.
That portfolio will now pass to another of her vice presidents, Maros Sefcovic, a commission statement said.
Sefcovic will also “temporarily” handle associated duties on climate and environmental policies until another Dutch commissioner is appointed, it said.
Von der Leyen hailed Timmermans as a “key member” of her commission whose work had allowed the European Union to make “great strides” towards its climate goals, and who influenced many other policy decisions.
The Dutch elections will take place on November 22. Timmermans, a center-left politician, will head a joint green and social democrat list at the polls.
His departure follows that of Mariya Gabriel, another commissioner on von der Leyen’s team who left in May to become Bulgaria’s deputy prime minister.
The European Commission — the EU’s powerful executive that sets trade policy and acts as market regulator for the entire bloc, often influencing global standards — is meant to be made up of 27 commissioners, one from each of the EU’s member countries.
Von der Leyen, a German, formed her team in 2019 at the start of its five-year mandate with eight vice presidents — three of which, including Timmermans, were executive vice presidents, senior over the others.
Another of the executive vice presidents, Margrethe Vestager, a Dane in charge of competition and antitrust issues, is angling to become the next head of the European Investment Bank, the EU’s lending institution.
Von der Leyen is viewed as having a strong chance of winning a second mandate as European Commission chief after EU elections next year but has not as yet declared whether she wishes to do so.