Tens of thousands of people rallied across Serbia for the ninth Saturday in a row, calling on President Aleksandar Vucic to step down.
A demonstration in the capital Belgrade was joined by students, who also called for the resignation of the Education Minister Mladen Sarcevic.
Organisers left three boxes outside the presidential office for people to voice their grievances.
The protests began in November following an attack on an opposition politician.
They have grown into a wider movement against the government with protesters accusing Vucic of stifling democratic freedoms, cracking down on opponents, and controlling the media.
The protesters march under the banner "one in five million" - a slogan coined after Vucic vowed not to yield to their demands "even if five million took to the streets".