Matilda Emilie Bertha McNamara (née Kalkstein, previously Bredt; 28 September 1853 – 1 August 1931) was an Australian political activist and writer. She was born in Prussia and arrived in Australia as a teenager. She became involved in the labour movement in the early 1890s until the 1920s, running a socialist bookshop in Sydney and authoring numerous political pamphlets; she was eulogised as "the mother of the labour movement". She was the mother of eleven children, and her sons-in-law included the writer Henry Lawson and politician Jack Lang.