Clinton will hold talks with President Ivo Josipovic, Prime Minister Zoran Milanovic, and Foreign Minister Vesna Pusic, with whom she met in Washington in March, praising the reforms Croatia had made on the road to NATO and European Union membership.
US officials have said a number of times they appreciate Croatia's contribution to the UN's peace operations and notably to NATO's ISAF mission in Afghanistan, where 320 Croatian troops are mentoring local soldiers and police.
In February, Clinton's deputy William Burns said in Zagreb that in 20 years of independence, Croatia had joined NATO and was on the threshold of the EU, which made it a model for neighbouring countries.
Clinton's first visit to Croatia will also be an opportunity to talk about the economic situation in the country, the State Department announced last week.
On his visit to Zagreb, Burns voiced hope that the investment climate in Croatia would improve. He also said Washington would try to revoke visa requirements for Croatian citizens.
Croatia already meets most of the requirements in that regard, but 6.3 per cent in rejected applications is more than twice the percentage allowed for Croatia to enter the category of countries which do not require visas for the United States.