Johanna (Hanna) Neumann (née von Caemmerer; 12 February 1914 – 14 November 1971) was a German-born mathematician who worked on group theory.

Neumann was born on 12 February 1914 in Lankwitz, Steglitz-Zehlendorf (today a district of Berlin), Germany.

As a result of her father's death in the first days of the First World War, the family income was small, and from the age of thirteen she was coaching school children.

The lecture courses in mathematics that she took in her first year were: Introduction to Higher Mathematics given by Georg Feigl; Analytical Geometry and Projective Geometry both given by Ludwig Bieberbach, Differential and Integral Calculus given by Erhard Schmidt, and the Theory of Numbers given by Friedrich Schur.

As a result of her first year work, Hanna was awarded three-quarters' remission of fees and a position as a part-time assistant in the Mathematical Institute's library.

[1] The Neumanns moved to Australia in August 1963 to take academic positions at the Australian National University in Canberra.

At the time of her appointment, the Department at ANU had recently started an honours programme in mathematics and were looking for a relatively senior pure mathematician to be responsible for that aspect of the courses.

She was able to introduce into the first year course, which had till then been entirely problem-oriented, a small strand of one lecture a week of an introduction to mathematics in the style of Feigl-Rohrbach.

She continued to develop a style of teaching which aimed at making the acquisition of very abstract ideas accessible through judicious use of more concrete examples and well-graded exercises.