The Aba Women's Riot of 1929 was triggered by:

The Aba Women's Riot of 1929 (also known as the Women's War or Ogu Umunwanyi) was triggered by the threat of direct taxation on women. The immediate cause was the action of Warrant Chief Mark Emeruwa in Oloko, who ordered a census of women and their property in late 1929. Women in the region interpreted this enumeration as preparation for imposing direct taxation on them, similar to the tax that had been levied on men since 1928 under the colonial Native Revenue Ordinance.

The women of Oloko and surrounding areas in southeastern Nigeria (primarily Igbo and Ibibio women) organised a massive protest that spread across the Owerri and Calabar provinces. They used traditional methods of protest such as "sitting on a man" (iri mgba), singing, dancing around Native Courts, and demanding the removal of Warrant Chiefs. The disturbances lasted from November to December 1929 and involved tens of thousands of women.

The protest was not primarily driven by anti-British nationalist propaganda, unemployment, or the expulsion of traditional rulers, although dissatisfaction with the Warrant Chief system (which had replaced traditional governance structures) was a contributing factor. The colonial government's response was violent, with soldiers killing dozens of women, which drew international condemnation and eventually led to reforms in the system of indirect rule in southeastern Nigeria.