Gertrude Mary Tuckwell CH (25 April 1861 - 5 August 1951) was a British trade unionist, social worker, author and magistrate.
Tuckwell was born in Oxford, the second daughter of the self-proclaimed "radical parson" William Tuckwell, master of New College School and chaplain at New College, Oxford. She was home-schooled in her family's Christian Socialist tradition and trained to be a teacher in Liverpool from 1881. She was a teacher at Bishop Otter College in Chichester from 1882 to 1884, and then taught at a working-class infant school in Chelsea until forced to stop by ill health in 1890.
From 1893, she became secretary to her aunt, writer, suffragette and trade unionist Emilia Dilke (wife of Sir Charles Dilke). She published The State and its Children in 1894, opposing child labour. She was involved with the Women's Trade Union League from 1891, and succeeded Emilia Dilke as its President in 1905. In 1908 she became president of the National Federation of Women Workers, and campaigned to protect women from industrial injuries such as phossy jaw. She retired in 1918, but continued to campaigning on public health issues. After Charles Dilke died in 1911, she co-wrote a two-volume biography with Stephen Gwynne.
After the Sex Disqualification (Removal) Act 1919 became law on 23 December 1919, and Tuckwell was one of the first seven women appointed as a Justice of the Peace, and she was the first woman magistrate in London. She was a founder member of the Magistrates' Association in 1920, and was a member of its council from 1921 to 1940. She was the chair of the National Association of Probation Officers from 1933 to 1941. In 1930 she was inducted into the Order of the Companions of Honour.