Gray decided to emigrate to Victoria (Australia), and with Charles Gavan Duffy, sailed in the Ocean Chief arriving in Melbourne in 1856. Gray took an active part in the solution of the land question on liberal lines, and was one of the founders of the Victoria Land League, under whose auspices was summoned a great assemblage of delegates from all parts of Victoria to discuss the land question with a view to promoting the settlement of a farming population on the public estate. The Land Convention, as it was called, met in Melbourne in 1857, and condemned the abortive Haines Land Bill then passing through the Lower House. Wilson Gray was elected the president of the Convention, which also passed resolutions in favour of manhood suffrage, equal electoral districts, abolition of property qualification, and payment of representatives.
Gray was member of the Victorian Legislative Assembly for Rodney from January 1860 to September 1862, when he went to Otago, New Zealand, and became a district court judge. He died in Lawrence, Otago, New Zealand on 4 April 1875.
- "The Late Mr. Wilson Gray". The Argus. Melbourne: National Library of Australia. 17 April 1875. p. 8. Retrieved 25 August 2014.
- Woods, Carole. "Gray, Moses Wilson (1813–1875)". Australian Dictionary of Biography. Canberra: Australian National University. Retrieved 22 December 2013.
- Mennell, Philip (1892). " Gray, His Honour Moses Wilson". The Dictionary of Australasian Biography. London: Hutchinson & Co. Wikisource
- "Gray, Moses Wilson". re-member: a database of all Victorian MPs since 1851. Parliament of Victoria. Retrieved 22 December 2013.
- "Reminiscences of Graytown (Spring Creek)". McIvor Times and Rodney Advertiser. Heathcote: National Library of Australia. 29 July 1915. p. 2. Retrieved 9 March 2017.