Poland's Mateusz Morawiecki will take part in the get-together alongside his Croatian counterpart Andrej Plenković, Italian Prime Minister Giorgia Meloni and Malta's Robert Abela, Polish state news agency PAP reported.
European Council President Charles Michel will attend the working dinner.
Earlier this week, Michel held similar mini-summits in Berlin and Copenhagen, and another such gathering is scheduled to take place in Paris, according to officials.
The Zagreb meeting is part of Michel's consultations with EU national leaders on the bloc's Strategic Agenda.
The talks began at an informal EU summit in Granada, Spain, in October, the PAP news agency reported.
During the gathering in Zagreb, Poland's Morawiecki and other EU national leaders are expected to discuss the bloc's political priorities for the 2024-2029 period, according to officials.
They will also talk about the key challenges facing the EU, as well as the bloc's sectoral policies and programmes, the PAP news agency reported.
Ahead of the meeting, Polish government spokesman Piotr Müller told reporters that Poland sought to ensure that "European integration recognises the sovereignty of nation states," amid proposed changes to EU treaties, such as the abolition of the principle of unanimity and veto rights in European Council voting in several policy areas.
(pm/gs)
Source: IAR, PAP, consilium.europa.au