Adnan bin Haji Mohd Ja'afar is a diplomat from Brunei who is the incumbent ambassador to Belgium since 2022, East Timor from 2019 to 2020, and high commissioner to Australia in 2008.

[1] On 29 October 2008, Sultan Hassanal Bolkiah handed over Adnan's letter of credentials, amid his appointment as the new high commissioner to Australia.

[2] After being appointed as the new ambassador to East Timor, on 15 January 2019, Adnan again received his letter of credentials at the Istana Nurul Iman.

[3] Adaljiza Magno's remarks at the farewell reception on 16 November 2020 noted that Ambassador Adnan has strongly advocated for Timor-Leste's ASEAN membership since its inception.

[1] As the non-resident ambassador to Luxembourg, he presented his credentials to Grand Duke Henri on 16 March 2022.