Karen Marie Christensen (3 February 1871, Kregme – 14 September 1945, Copenhagen) was a Danish trade unionist, women's rights activist and politician.
Appalled at the slave-like conditions that servants in Denmark lived under in the 19th century, in 1899 she founded a trade union for maids in Copenhagen (Danish: Københavns Tjenestepigeforening, later incorporated into FOA).
Christensen's main goals were to provide maids with stable pay and working conditions and to have the 1854 Servants Law (Tyendeloven) repealed.
The law put domestic workers at a disadvantage compared to other professions, giving employers the right to discipline their servants, and to keep a life-long conduct book (skudsmålsbog) recording an assessment of their work.
The commission's work between 1905 and 1910 did not immediately lead to results, nor did the 1921 Assistants Law (Medhjælperloven) fully satisfy Christensen's desire for labour reform for domestic workers.
When women's suffrage in parish and municipal elections began to be discussed in 1901–1904, Christensen was amongst those who launched a campaign to ensure that servants were also included.