Grabar-Kitarovic, who ends a visit to the United States this weekend, said she was optimistic her country would meet all the requirements and implement reforms needed to get membership of the European Union.
"We believe we can complete the process of negotiations within about 2 1/2 to three years," the minister said. "We don't want to obsess with dates but we do have an overall framework in mind," she added.
Croatia began negotiations with the European Union last October, the only country in the Western Balkans to have done so, and Grabar-Kitarovic said she hoped the EU would adapt its own rules to allow for Croatia's accession.
A key obstacle for Croatia's EU and NATO membership was removed last December with the arrest in Spain's Canary Islands of former general Ante Gotovina.
The Croatian minister, who has also met senior US defence and White House officials during her visit to Washington, said the former general's arrest proved the "honest intentions" of her government to cooperate fully on the issue.
Grabar-Kitarovic said she hoped this November's NATO summit in Riga, Latvia, would result in a "strong message of encouragement" that Croatia was doing everything it could to meet membership requirements.