Jack the Rammer, alias of William Roberts, was a bushranger in the Monaro District near Cooma in New South Wales during the mid-1830s.

Born and raised in England, William Roberts was a cooper by trade, with a wife and three children, when he was sentenced seven years for stealing a bucket and transported to New South Wales.^[1] He arrived in Australia in September 1833, and escaped from his first convict assignment the following year.^[1] Placed in Goulburn Jail he met fellow convict Joseph Keys and the pair escaped together.^[1]

Roberts and Keys headed for the Monaro District, where they met up with Edward Boyd, and began bushranging.^[1] In December 1834, the three "stuck up" the station of Joseph Catterall, badly wounding the station overseer Charles Fisher Shepherd, who, in turn, shot and killed Roberts.^[1][2] In January 1835, troopers caught up with Boyd and Keys, and Boyd was killed.^[1] Keys was captured and pleaded guilty.^[3]