Zaini bin Haji Ahmad (born 21 January 1935) is a Bruneian politician, civil servant and writer who served on the Partai Rakyat Brunei's (PRB) Executive Committee and founding the anti-government newspaper Suara Bakti, he was detained in Brunei, escaped to Malaysia in 1974, participated in the PRB's UN Mission in 1976, and was considered the A. M. Azahari's personal assistant.

He chose to rejoin the PRB after making an attempt to start his own political party in December 1961, followed by being elected to the position of District Councillor in August 1962.

[6] When the Brunei revolt began in 1962, he was in Manila as part of the A. M. Azahari mission to the Headquarters of the United Nations in New York City,[1] supporting the Malaysia Agreement.

Amnesty International, the United Nations Human Rights Committee, and the Commonwealth Relations Office in London all made unsuccessful attempts to secure his release.

[3][7] On 12 July 1973, the day of Sultan Omar Ali Saifuddien's birthday, Zaini and six other senior PRB detainees of the Berakas Detention Camp,[8] including Yassin Affandi, escaped by sea to nearby Limbang in Sarawak, thanks to an operation led by the nephew and brother of PRB leader Azahari, Sheikh Saleh Sheikh Mahmud.

[3] In exile in Malaysia, Zaini and a few other PRB members who fled with him revived the party and carried on with their political activities, calling for Brunei's independence and appealing to various international bodies and nations, including the United Nations (March 1975, July 1975, November 1975, and October 1977), the Commonwealth (March 1975), the Non-Aligned Movement Summit (July 1976), and the Muslim Foreign Ministers' Conference in Kuala Lumpur (1974).

After being prevented from pursuing his dream of earning a doctorate abroad, Zaini enrolled at the University of Malaya in 1988 to work under Khoo Kay Kim on a dissertation about the history of the PRB.

After his recovery, he lived in a peaceful retirement in Bandar Seri Begawan with his oldest son and family, working at the Brunei History Centre to prepare his PhD thesis for publication.

[3] Isa bin Ibrahim, the Minister of Home Affairs, issued an order in 1990 forbidding the importation, sale, or distribution of Pertumbuhan Nationalisme Di Brunei (1939–1962) and Triwarna, two of Zaini's works.