Norway takes the lead moving up from second place in 2014, recording the best results in all five indicators: health of mother and child, access to education and the political and economic status of women.
Somalia was ranked the worst country with 15% of children not living to see their fifth birthday, the organisation's reports says.
Croatia is ranked 30th alongside Korea and of the countries in the region, only Slovenia fared better, being ranked 15th, while Serbia was ranked 35th, Macedonia 37th, Montenegro 42nd and Bosnia and Herzegovina 54th.
According to the so-called Mother Index, one in every 5,200 women in Croatia die due to complications during pregnancy, 4.5 children in every 1,000 die before turning five, formal education lasts 14.8 years and women account for 25.8% of government at the state level.
The gap between the health of the richest and poorest is just as stark in big cities in some of the wealthiest nations, according to the report.
"If the world’s going to complete the task of ending preventable child and maternal deaths, we have to find better ways of getting health care to urban populations, regardless of income," says Jasmine Whitbread, CEO of Save the Children International.