Tasnor Ivan "Tas" Bull (31 January 1932 – 29 May 2003) was an Australian trade union leader, serving as General Secretary of the Waterside Workers' Federation from 1984 to 1993.

Technological change was greatly reducing the size of the workforce, while at the same time there was political pressure to reform waterfront work practices to make the Australian transport sector internationally competitive.

In 1993 the WWF amalgamated with the SUA to form the Maritime Union of Australia (MUA).

From 1972 onwards he worked with the International Transport Workers' Federation, and for ten years until 1993 represented the Asia/Pacific region on its executive board.

Following his retirement in 1993 Bull remained active in various left-wing and union causes, and published his autobiography Life on the Waterfront in 1998.