Croatia is down one place from the previous ranking. The Global Peace Index has been published for nine years and evaluates peace in 162 countries based on 23 indicators, ranging from civil strife, crime and military spending to involvement in armed conflicts and relations with neighbors. The index covers 99.6% of the global population.
Croatia has an average score of 1.55 (1 is the best and 5 the worst), and it scored the best (1) in categories such as the number of murders, involvement in international conflicts, political terror, arms export and import, terrorism and the number of displaced persons.
It scored the worst (3.5) in terms of the number of police and security staff, perception of crime and access to weapons (3.0).
Europe has kept the status of the world's most peaceful region, with 15 of the ranking's 20 top countries being European countries.
The three most peaceful countries in the world are Iceland, Denmark and Austria. They are followed by New Zealand, Switzerland, Finland, Canada, Australia, Japan and the Czech Republic.
Syria continues to be at the bottom of the ranking, and above it are Iraq and Afghanistan.
Of Croatia's neighbours, Slovenia is ranked 15th, Hungary 22nd, Italy 36th, Serbia 46th, Bosnia and Herzegovina 53rd, and Montenegro 57th.
The worst ranked European countries are Kosovo, 69th, Macedonia, 71st, and Ukraine 150th.
IEP says that growing differences in the peace indexes of rich European countries and poor African and Middle East countries, involved in escalating civil wars and permanent refugee crises, have resulted in an increasingly divided world.
"The intensity of armed conflict increased dramatically, with the number of people killed in conflicts globally rising more than 3.5 times, from 49,000 in 2010 to 180,000 in 2014," the IEP says, underlining that the impact of violence on the global economy reached 13.4% of global GDP.
"2014 was marked by two contradictory trends: on the one hand, many countries in the OECD achieved historic levels of peace while on the other, strife-torn nations, especially in the Middle East, became more violent. This is a real concern; as these conflicts become even more intractable they then spread terrorism to other states."
The jihadism of Islamic extremists is the main reason for a sharp rise in the number of people killed in armed conflicts in 2014, the IEP says, noting that in Syria alone 70,000 people were killed.