Mary Lee (née Walsh) (14 February 1821 – 18 September 1909) was an Irish-Australian suffragist and social reformer in South Australia.

When he fell ill in 1879, Lee, now a widow, and her daughter, Evelyn, immigrated to Adelaide aboard the steamship Orient[3] on its maiden voyage.

[5] In 1883 Mary Lee became active in the ladies' committee of the Social Purity Society of the reverend Joseph Coles Kirby.

The group's success was a passage in the 1885 Criminal Law Consolidation Amendment Act that raised the age of consent from 13 to 16, i.e., which made it illegal for a man to have sex with a girl under 16.

Her own letters and reports of her speeches show that she was an astute and logical woman, employing sound argument, wit and humour in her correspondence and public speaking.

Such is the basis of our reverence for the person of women and of our estimate of her work.Lee was active in advocating the rights of the working class, publishing the following thoughts in The Barrier Miner in respect of the 1892 Broken Hill miners' strike: ... Sir, this strike has one feature which renders it more profoundly interesting than any of its predecessors...which must secure it a prominent and distinguished page when the history of these colonies shall be written.

On 23 August 1894 when the Adult Suffrage Bill was read in the South Australian parliament, the women presented the great petition.

The bill passed on 18 December 1894, granted women the right to vote and stand for parliament, and South Australia was the first legislation worldwide to do so.