Hong Kong public high school students began attending classes on Wednesday, part of a phased reopening after the financial hub successfully tackled its coronavirus outbreak.
Hundreds of secondary schools opened their doors on Wednesday for senior students, the first classes in the state sector since late January.
Younger students will return in stages over the coming weeks, while fee-paying international schools have already restarted classes.
Hong Kong was one of the first places to be hit with the coronavirus when it spread from central China.
But health authorities have managed to keep a mass outbreak at bay with just over 1,000 infections and four deaths.
The semi-autonomous city went into a partial lockdown in March but businesses have mostly reopened in recent weeks.
Local transmissions of the COVID-19 disease have all but ended — the city has recorded 11 days straight of zero local infections.
The few cases that are documented are found within people returning from overseas who are swiftly tested on arrival at the airport, and quarantined if necessary.
The resumption of classes on Wednesday coincided with a debate in the legislature over a proposed law banning insults to China's national anthem.
The South China Morning Post reported some students held banners calling for democracy as they walked to school on Wednesday morning.