The midfielder suffered a hamstring problem during QPR's play-off final victory at the weekend, meaning he will miss the tournament in Brazil
Kranjcar has been an integral part of his national team in recent years and was preparing for his second World Cup appearance.
However, the Croatian Football Association announced on Monday that the former Tottenham man, who has 81 international caps, will not travel to Brazil following an MRI scan in Zagreb.
"Croatian midfielder Niko Kranjcar will miss the World Cup due to hamstring injury," the body posted on their official Twitter account.
Croatia will appear in the competition's opening game against hosts Brazil on June 12.