Bill 21 prohibits public officials in positions of authority - like judges, police officers, teachers and public servants - from wearing symbols such as the kippah, turban, or hijab while at work.
It also requires public services to be provided and received with the face uncovered.
For Bill 21, the Quebec government invoked the "notwithstanding clause" - a part of the Canadian constitution that allows government to override "fundamental freedoms" of religion, expression, and association; the right to life, liberty and security of the person; and freedom from discrimination.
It essentially serves an opt-out option that prevents courts from striking down the legislation on constitutional grounds.
Bill 21 does not mention any specific religion and would include symbols worn by a person of any faith, including Christian, and affirms the religious neutrality of the state.
But critics argue it targets mostly religious minorities, and especially women of Muslim faith.
The law has faced a number of legal challenges in Quebec and Canada's Supreme Court has agreed to take up the case, which will hinge both on the law itself and the use of the notwithstanding clause.
The debate over secularism - broadly, the principle that religion and government institutions should be separate - has played a significant role in the province's public discourse for almost two decades.
Known in the majority French-speaking province as laïcité, it has been an important value in Quebec society since the 1960s as the Catholic Church's strong influence began to wane in the province.
A September survey by polling firm Leger, commissioned by media outlets Le Journal de Montréal and TVA, indicated that 68% of respondents thought secularism was an important value.
Similar legislation to Bill 21 is in place in various countries across the European Union.
France passed a ban on veils, crosses and other religious symbols in schools in 2004 and on face covering in public spaces in 2010.