Käthe Petersen (born 13 May 1903 in Elmshorn; died 10 January 1981 in Hamburg) was a lawyer and social politician. From 1923 to 1926, Petersen studied law and political science, psychology and economics at the universities of Giessen, Freiburg in Breisgau and Hamburg. Petersen then embarked on the higher administrative career and was employed in Hamburg as an assessor in the legal department of the Social Welfare Authority in 1932, then, in 1937, Petersen was a deputy director of the welfare department in the , was promoted to Senate Councilor there in 1939 and took over this year the management of health and vulnerable care. She was involved in the creation and development of social assistance law, the section "Vulnerability" in the (BSHG) being conceptualized by Petersen. Petersen was