Apart from Zagreb, where teachers, students and parents were to address the rally, protests were also held in Osijek, Slavonski Brod, Virovitica, Krizevci, Varazdin, Porec, Pula, Rijeka, Zadar, Split, Korcula, Dubrovnik as well as London, Paris, Budapest and Shanghai.
The protesters in Zagreb filled the central city square, blowing whistles and trumpets and carrying balloons and banners supporting the reform.
Banners with a different position could also be seen, with one of them reading "No to the reform according to a Serb plan and programme, it's destruction of the Croatian language, culture and state."
Just before the protest, representatives of the protest organisers told reporters that the gathering was not politically motivated.
Nikola Baketa, a representative of the Croatia Can Do Better initiative, the protest organiser, gave the parliament until Friday to adopt a resolution on education as a national interest, saying that otherwise, the initiative would make a decision on further action.
The initiative also wants experts rather than politicians to have the final say in the reform process.
Asked if the opposition Social Democratic Party (SDP) was behind the protest, Baketa said that the party was incapable of organising such a protest.
Eli Pijaca Plavsic said that the current government had stopped and launched the reform five times in the last six months, but that the previous, SDP-led government had not been any better either.
Disputes over the curricular reform, which is designed to modernise the education process and teach children to think critically, erupted after the parliamentary Committee on Science and Education concluded that the national expert team in charge of the reform should be expanded with ten new members. This prompted the team's head, Boris Jokic, to say that they would not tolerate political pressure, regardless of whether it came from the political left, right or centre and that professionals should always come before politics.
The protest organiser, the Croatia Can Do Better initiative, comprises more than 300 civil society organisations and unions.
They said that the protest was not a feast, as claimed by Science and Education Minister Predrag Sustar, but a warning from citizens against using education as an instrument in political quarrels.
They underline that they want a transparent and professional process of political decision-making in the field of education.
As for yesterday's meeting between President Kolinda Grabar-Kitarovic, Science and Education Minister Predrag Sustar and the resigned head of the national expert team for the curricular reform, Boris Jokic, the initiative's representatives said they did not see any difference between the latest expressions of support for the reform and three previous statements.
That makes it clear that Sustar is incapable of running the sector entrusted to him and should either step down or start protecting education and the reform process from political pressure, they said.
More than 35,000 citizens have so far signed an on-line petition of support for Jokic and his team.