The report, released on Wednesday, ranked Nigeria 148 out of the total 163 countries surveyed.
Iceland is the most peaceful country, closely followed by New Zealand and Austria while Syria is ranked least peaceful, coming after Afghanistan and South Sudan respectively.
In Sub-Sahara Africa, Nigeria is ranked 40 out of 44 countries, with Mauritius topping the list, while South Sudan is ranked least.
According to the report produced by the Institute for Economics and Peace (IEP), global level of peace has deteriorated by 0.27 percent in the last year, marking the fourth successive year of deterioration.
It also said the world is "less peaceful today than at any time in the last decade".
It added that 92 countries deteriorated, while only 71 improved. Nigeria is one such countries, up one place from its 2017 ranking of 149.
In 2016, Nigeria was pegged at 149, while the figure was 151 for both 2015 and 2014.
The report said the global economic impact of violence was $14.76 trillion PPP in 2017, equivalent to 12.4 percent of global GDP, or $1,988 per person.
The report covers 99.7 percent of the world's population and uses 23 qualitative and quantitative indicators from "highly respected sources" to compile the index. These indicators are grouped into three key domains: 'ongoing conflict', 'safety and security', and 'militarisation'.
All three domains deteriorated over the last year.
"There's been a gradual decline in peacefulness over the last decade," said Steve Killelea, head of IEP.
"The reason for this slow, gradual decline in peacefulness really comes back to the conflicts in the Middle East and North Africa, and the spillover effects into other areas."