The Department for Energy Security and Net Zero (DESNZ) is a ministerial department of the Government of the United Kingdom. It was established on 7 February 2023 by a cabinet reshuffle under the Rishi Sunak premiership. The new department took on the energy policy responsibilities of the former Department for Business, Energy, and Industrial Strategy (BEIS).

British Prime Minister Rishi Sunak carried out the first cabinet reshuffle of his premiership on 7 February 2023. The reshuffle saw a significant restructuring of a number of government departments, and gave Sunak the opportunity to fill the vacancy left by Nadhim Zahawi after he was dismissed as Chairman of the Conservative Party and Minister without Portfolio on 29 January 2023, following a scandal surrounding his tax affairs.