Global citizenship and residence advisory firm Henley & Partners produces the Henley Passport Index each year using data from the International Air Transport Association.
The 2018 edition ranked Denmark's passport as the third best in the world as it provides visa-free or visa-on-arrival access to 187 countries. That equals last year's third place, though the number of accessible countries has increased overall from 174 in 2017.
Denmark shares third place with Italy, Finland, France, Spain, Sweden and South Korea.
Scandinavian neighbours Norway both ranked fourth, while the UK and US (both joint fourth) were also slightly behind Denmark in terms of visa-free access.
Singapore and Germany were second (providing access to 188 countries), while Japan was first (189).
Schengen Area countries have traditionally topped the index due to providing open access to large parts of Europe, Henley & Partners noted, but Asian countries are catching up thanks to strengthened international trade and diplomatic relations.
One European country that could see its position in the ranking weaken in the coming years is the UK, with Brexit potentially making trips abroad more complicated.
The Henley index surveys 199 different passports and the access they provide to 227 different destinations.