William "Billy" Hull (born 1912) was a loyalist activist in Northern Ireland. Hull was a leading figure in political, paramilitary and trade union circles during the early years of the Troubles. He is most remembered for being the leader of the Loyalist Association of Workers, a loyalist trade union-styled movement that briefly enjoyed a mass membership before fading.
A native of Belfast, Hull came from the Shankill Road, a staunchly loyalist and working class area in the west of the city. Hull was well known for his heavy build, and he was said to weigh as much as twenty stone. He was a member of the Orange Order.
Hull worked at the Harland and Wolff engine shop in Belfast, and became the convenor of shop stewards there. A supporter of working class and trade union politics, Hull became a member of the Northern Ireland Labour Party in 1948. He maintained his membership of the party until the early 1970s, when he resigned in protest at the Northern Ireland policy of the Harold Wilson government and the British Labour Party.
Hull was also active in loyalist paramilitarism and around 1970 he helped to establish the Workers' Committee for the Defence of the Constitution (WCDC), a loyalist trade union of which he was joint leader along with Hugh Petrie of Short Brothers. In February 1971, he led a march of 9,000 shipyard workers to demand the introduction of internment in the aftermath of the 1971 Scottish soldiers' killings. Hull's march was one of the major factors in the resignation of James Chichester-Clark as Prime Minister of Northern Ireland.