Rebeca Gyumi and her organisation, Msichana Initiative (named for the Swahili word for "girl") campaigned for the overhaul of Tanzania's Marriage Act of 1971, which allowed girls as young as 14 to be married with their parents' consent. The law was changed in 2016, and in 2018 Gyumi was awarded the UN Human Rights Prize. Msichana also campaigns on other issues including transportation for rural women.