Elise Ottesen-Jensen, also known as Ottar (2 January 1886 − 4 September 1973), was a Norwegian-Swedish sex educator, journalist, and anarchist agitator, whose main mission was to fight for women's rights to understand and control their own body and sexuality.

Her personal motto was "I dream of the day when every new born child is welcome, when men and women are equal, and when sexuality is an expression of intimacy, joy and tenderness.

"[5][1] A vicar's daughter, Ottar was born Elise Ottesen in the municipality of Høyland (incorporated into Sandnes in 1965) in Rogaland county, Norway.

She was Immanuel Ottesen and Karen Arselle Essendrop's 17th out of 18 children, and as was customary in Norway at that time she was named Elise after her sister who died as an infant the year before.

For this, Ottar could never forgive her father, and the fate of her sister became a strong driving force for her commitment to the struggle for women's rights.

[5] By the end of the First World War, in 1913, Ottar met and developed a close friendship with the Swedish anarcho-syndicalist peace agitator Albert Jensen [sv].

[13] She was awarded the Illis quorum by the Swedish government in 1951[14] and honorary doctorate in medicine in Uppsala in 1958.