Abdul Aziz bin Haji Umar (born 20 March 1936) is a Bruneian aristocrat and politician who held a wide range of positions in the government of Brunei.

Beginning his career in the civil service with his first appointment in 1964, he held various roles until Brunei's independence in 1984, including serving as the acting menteri besar (chief minister) from 1981 to 1983.

As one of the nation's 'founding leaders,' he was part of a group of Bruneians with Western educations who significantly contributed to the country's development after gaining independence.

[5] In January 1982, Abdul Aziz made an official visit to Kuala Lumpur,[8] which helped to strengthen ties between Brunei and Malaysia, focusing on administrative training, educational collaboration, and representative exchanges.

Despite the government offering higher pay and benefits, private companies struggled to recruit workers due to a lack of dedication and experience.

Abdul Aziz's remarks reflected his growing concern about the spread of these societal issues, such as an increase in drug-related convictions, which had not been a significant problem just a few years earlier.

[15] In April 1990, he announced the gradual phasing out of coeducational schools to align with Islamic principles and introduced the concept of MIB into the education system, establishing it as a core subject for all students.

[17] These actions can be seen as cautious steps towards solidifying MIB as the national narrative while laying the groundwork for a gradual shift towards constitutionalism, provided the monarchy continues to uphold its image as the protector of Malays and the guardian of the Islamic faith.

Abdul Aziz also chaired Global Evergreen, a business established to address the fallout from the Amedeo Development Corporation (ADC) crisis, which was headed by Prince Jefri Bolkiah.

Some speculated that this change reflected the rise of more conservative factions around the sultan, coinciding with an increased public profile and influence of Prince Mohamed Bolkiah in the nation's political and economic affairs.

[28]With this settlement, Insha Allah (God willing), all assets such as hotels, buildings, lands, shares and other similar assets in Brunei Darussalam and overseas, which were acquired with money derived from BIA and are at present under the control of His Highness (Prince Jefri) and his family, will be returned to the BIA.Abdul Aziz served as the chairman of the Yayasan Sultan Haji Hassanal Bolkiah's administrative committee for two terms, from 2000 to 2004 and from 2004 to 2008.

[31] On 1 May 2002, Abdul Aziz addressed the issue of rising youth unemployment, stressing the need for stronger cooperation between the public and private sectors, particularly with the Chinese Chamber of Commerce.

[32] On 10 April 2003, Abdul Aziz signed a memorandum of understanding in Jakarta, focusing on defence cooperation on behalf of Brunei.

[5] Reports suggest that he lost his position due to allegations that he had impeded economic growth by placing greater emphasis on religious studies over science and technology in the curriculum.

[37] On 11 April 2021, he emphasised the need for the Brunei Malay Teachers Association (PGGMB), established 82 years ago, to adapt to modern demands in order to support national progress.

[43] On 5 September 1977, Abdul Aziz was honoured by Sultan Hassanal Bolkiah with the manteri title of Pehin Orang Kaya Laila Wijaya, bearing the style Yang Dimuliakan.