The Black Sash was a women's protest organisation and political pressure group, which originated in 1955. It was initially called the Women's Defense of the Constitution League, in response to the Senate Bill, a piece of Apartheid legislation, which was introduced into Parliament. This was seen as a violation of the legal provisions of the constitution, and as the breaking of a solemn pledge to the coloured people whose franchise rights had been entrenched in the South Africa Act of 1910.

The Black Sash women, so called from the black sash worn over the right shoulder, were conspicuous during vigils and silent poster demonstrations, standing up to protest in public places against unjust laws, often referred to by them as 'Sashing'. But the major part of the Sash work was behind the scenes, and consisted of informing the public by means of handouts, pamphlets, memos, letters, articles and statements to the press, and of delegations to government ministers

An important aspect of the Black Sash work was the Advice Offices which operated in various parts of the country. These were an attempt on the part of members to mitigate the effects of discriminatory legislation and to help black people find their way through the maze of the Pass Laws and enjoy at least those few rights to which they were entitled. Other problems handled by the Advice offices included employer/employee problems, workmen's compensation, unemployment insurance, and pensions