The Colony of Tasmania (more commonly referred to simply as "Tasmania") was a British colony that existed on the island of Tasmania from 1856 until 1901, when it federated together with the five other Australian colonies to form the Commonwealth of Australia. The possibility of the colony was established when the Parliament of the United Kingdom passed the Australian Constitutions Act in 1850, granting the right of legislative power to each of the six Australian colonies. The Legislative Council of Van Diemen's Land drafted a new constitution which they passed in 1854, and it was given Royal Assent by Queen Victoria in 1855. Later in that year the Privy Council approved the colony changing its name from "Van Diemen's Land" to "Tasmania", and in 1856, the newly elected bicameral parliament of Tasmania sat for the first time, establishing Tasmania as a self-governing colony of the British Empire. Tasmania was often referred to as one of the "most-British" colonies of the Empire.

The Colony suffered from economic fluctuations, but for the most part was prosperous, experiencing steady growth. With few external threats and strong trade links with the Empire, the Colony of Tasmania enjoyed many fruitful periods in the late nineteenth century, becoming a world-centre of shipbuilding. It raised a local defence force which eventually played a significant role in the Second Boer War in South Africa, and Tasmanian soldiers in that conflict won the first two Victoria Crosses won by Australians. Tasmanians voted in favour of federation with the largest majority of all the Australian colonies, and on 1 January 1901, the Colony of Tasmania, became the Australian state of Tasmania.