Mary Nonyembezi Ngalo (nee Plaatjie) was a South African anti-apartheid activist and was also active in fighting for women's rights. Mary Nonyembezi Margaret Ngalo (nee Plaatjie) was born in Cradock, Eastern Cape, South Africa. She was the daughter of Tom Cetywayo and Lillian Fihliwe "Leah" Plaatjie. She met and married Zenzile Ngalo in Cradock.She started participating in politics at an early age. She joined the ANC Youth League. As a leader of women in Cradock, she was elected as the branch secretary of the ANC Women's League. She held her post till she fled Cradock in 1961. She mobilised hundreds of women to join the Federation of South African Women which was a non-racial body of women who fought in the struggle against Apartheid. The ANC Women's League launched the Beer Hall Boycott