Montague David "Monty" Miller, born 7 July 1839 in Van Diemen's Land (present day Tasmania), was an Australian unionist, secularist and revolutionary socialist chiefly active in the states of Victoria and, in his most productive period, in Western Australia. His activism with unions and the Industrial Workers of the World (IWW), during the early years of the twentieth century, saw him acting as a speaker and organiser for these sometimes illegal groups, leading to his conviction for conspiracy in 1916.
Miller's parents took him to the Port Philip District (later known as Victoria), at the age of six weeks. They lived first at Port Fairy, and then moved to the Ballarat goldfields where Miller was apprenticed to a joiner. Miller's father was himself a carpenter. Miller would work at his trade throughout his life, as a contractor where possible to avoid having to work under a master, although he is also reported as having turned his hand to a variety of bush labour.
At the age of 15, Miller took part in the — an uprising at Ballarat by self-employed miners, who were opposed to the policies of an authoritarian British colonial regime in Victoria. During the rebellion, he was involved in hand-to-hand fighting against members of the British 40th Regiment. Although the rebellion failed, it contributed to the introduction of democracy in Australia.
Miller married in Ballarat at the age of twenty and shortly afterwards moved to Melbourne. He was early exposed to Chartist ideas which were influential in Ballarat at the time, and also early adopted his lifelong atheism. The building trades, to which Miller belonged, were at the forefront of early Victorian unionism.
His political career involved working with the unions and the Australian Labor Party, but he maintained a disillusioned view of political parties and structures, moving within the radical spectrum. He was a founding member of the Melbourne Anarchist Club in 1886. He appears to have moved to Perth in 1897, the end of an economic boom in the state, a period of political reformations and larger scale social change.