Mary Dorothea Frederica Steen (28 October 1856 – 7 April 1939) was a Danish photographer and feminist.

She also played an important part in improving conditions for female workers and encouraging women to take up the profession of photography.

[1] In her late teens, she moved to Copenhagen where she graduated at the Women's Business School but she soon found out that she was not made for office work.

[2] In 1888, she became the first female court photographer for Princess Alexandra[3] who was to marry Great Britain's Edward VII.

Around 1895, Princess Alexandra invited her to London where she photographed members of the royal family, including Queen Victoria at Windsor Castle.

In 1891, she received a grant from the Reiersenske Fond, a trade association, which allowed her to travel to Germany and Vienna.