The Black Sea nation has been mired in political turmoil since parliamentary elections in 2024, which the opposition says were rigged.
Opposition parties have refused to recognise the new parliament and government.
Tensions deepened after the government shelved EU membership talks with Brussels until 2028.
That triggered months of street protests followed by a crackdown on demonstrators, opposition figures, civil society groups and independent media.
Waving Georgian and EU flags, thousands of protesters marched through central Tbilisi before staging a rally outside parliament amid a heavy police presence, an AFP journalist saw.
Many held placards reading: “We are Europe” and portraits of jailed former president Mikheil Saakashvili, who pushed for close ties with the West while in office.
“We’ve been out in the streets for more than 500 days, and we’ll keep coming out for as long as it takes to defend Georgia’s European future,” 20-year-old student Maya Khidesheli told AFP.
“People will win in the end. No authoritarian government can stand up to a united people — and we are united,” said another protester, 59-year-old chemist Irakli Nanadze.
The rally was organised by an alliance of opposition parties that has recently been working to overcome divisions and forge a united front against the government.
Critics accuse the ruling party of democratic backsliding and moving the country closer to Moscow, allegations the government denies.
Georgian Prime Minister Irakli Kobakhidze said last year that Tbilisi’s path towards joining the EU was “steady and irreversible”, despite Brussels effectively freezing Georgia’s accession process.
Joining the EU is inscribed in the country’s constitution and, according to opinion polls, supported by more that 80% of the population.
Last year, the governing Georgian Dream party announced plans to ban its main opposition rivals, a proposal widely condemned by critics as a further step toward authoritarian rule.
Western countries have denounced the erosion of democratic practices in Georgia and sanctioned Georgian Dream officials.