"Turkey is secular and will remain secular," shouted protesters on Saturday as they waved national flags and banners of Mustafa Kemal Ataturk, the founder of the republic, at his mausoleum in the capital, Ankara.
Turkey's secular establishment, which includes army generals, judges and university rectors, sees the headscarf as a symbol of radical Islam and believe it threatens the country's secular order.
Turkey is 99 per cent Muslim. As recently as 1997, Turkey's army generals, acting with public support, ousted a government they deemed too Islamic.
Opinion polls suggest a majority in the country of 70 million, where around two thirds of women don the headscarf, back a relaxation of the ban.
The headscarf debate is central to Turkey's complex identity, as the young democracy struggles to meet the demands of both a pious Muslim population and the secular, pro-Western elite.
Financial markets are nervously watching the debate.
Denying any Islamic agenda, the AK Party, which has long wanted to lift the ban on the headscarf, says the issue is a matter of religious and personal freedom.
The decision by the AK Party - headed by Tayyip Erdogan, Turkey's prime minister - to push the reform reflects its confidence after it won a sweeping re-election last July.
But pressure has intensified this week with university rectors warning that allowing female students to wear the Muslim headscarf at university would provoke campus chaos and street violence.
Secularist professors have also threatened not to allow women into class if they wore the garment.
"Unfortunately an important part of the debate going on these days is weakening Turkey's image abroad," Ali Babacan, Turkey's foreign minister whose wife wears the headscarf, said.
The government wanted to expand freedoms to turn Turkey into a "first-class democracy where freedoms in all fields are enjoyed fully", he said.
Members of Turkey's judiciary and top businessmen have already slammed the headscarf plan and the main opposition party, the Republican Peoples' Party (CHP), has said it will go to the constitutional court to block the reform.
Under the government plan, the ban on the headscarf would remain for teachers and civil servants.
Turkey's military has so far refrained from directly commenting on the headscarf proposal.