Sir Stephen Augustus Lovegrove GCMG KCB (born November 1966) is a British civil servant who was the UK National Security Adviser from March 2021 to September 2022.

He led the Shareholder Executive from 2007 to 2013, and then had permanent secretary roles at the Department of Energy and Climate Change and the Ministry of Defence.

Lovegrove was educated at Warwick School and at Corpus Christi College, Oxford, where he was awarded a first class degree in English in 1989.

He was appointed as Permanent Secretary of the Department of Energy and Climate Change with effect from 4 February 2013.

[1] In March 2016, after three years in that post, the Government announced his appointment as Permanent Secretary of the Ministry of Defence.