Israel, Finland and Sweden are seen as leading the way in "cyber-readiness", according to a major new security report.
The McAfee-backed cyberdefence survey deemed China, Brazil and Mexico as being among the least able to defend themselves against emerging attacks.
The rank is based on leading experts' perception of a nation's defences.
The report concluded that greater sharing of information globally is necessary to keep ahead of threats.
It also suggests giving more power to law enforcement to fight cross-border crime.
The UK, with a grading of four out of five, ranks favourably in the survey - along with the USA, Germany, Spain and France.
The study was carried out by the Security and Defence Agenda think tank and its rankings are based on the perceived quality of a country's cyber-readiness - the ability to cope with a range of threats and attacks.
"The subjectiveness of the report is its biggest strength," explained Raj Samani, McAfee's chief technology officer.
"What it does is give the perception of cyber-readiness by those individuals who kind of understand and work in cyber security on a day-in, day-out basis."
A good score depends on having basic measures like adequate firewalls and antivirus protection, and more complex matters including well-informed governance and education.
Sweden, Finland and Israel all impressed the report's experts - despite the fact that the latter receives reportedly over 1,000 cyber attacks every minute.
Isaac Ben-Israel, senior security advisor to Israel's prime minister Benjamin Netanyahu, is quoted in the report as saying: "The hacktivist group Anonymous carries out lots of attacks but they don't cause much damage. The real threat is from states and major crime organisations."
He added that the country has set up a cyber-taskforce responsible for assessing threats to key infrastructure such power production and water supplies.
At the other end of the security scale, Mexico ranked as least prepared to cope with the cyber threat - a situation which is blamed on the country's authorities needing to overwhelmingly focus on the country's gang and drugs problems.
China is regarded by some Western observers as an aggressor in cyberspace.
But one expert Peiran Wang said the country was itself vulnerable because it lacked a joined up strategy.
"The Ministry of Public Security, the Ministry of Industry, the Ministry of State Security and even the military are involved and they don't communicate well," said Peiran Wang, a visiting scholar at Brussels' Free University.
In the UK, the report praised a £650m investment programme in cyber security.
However, the Home Office's plans were criticised by information security expert Peter Sommer.
"A great deal depends on co-operation from the private sector, which controls about 80% of the critical national infrastructure.
"Over half of the new funding will go to the 'secret vote', the intelligence agencies, where value for money will be difficult to investigate. I would have preferred more emphasis on public education - helping potential victims help themselves."
Among the report's conclusions is the recommendation that greater efforts be made to improve cross-border law enforcement.
"Cybercriminals route their connection through multiple different countries," said Mr Samani.
"If criminals are particularly clever, they go through countries where they know there isn't any co-operation."
"The bad guys share information - we need to do the same as well."
Dr Joss Wright from the Oxford Internet Institute welcomed the report's findings. However, he had serious doubts over the feasibility of its suggestions.
"They're recommendations that people have been saying for maybe 10 years," he told the BBC.
"I would love to see good information sharing - but when you're talking about national security, there's a culture of not sharing.
"They're not suddenly going to change 70, 100, 1000 years of military thinking."