The Brown University survey, in its fourth year, measures the online performance of government in 198 countries. Professor Darrell West and a team of researchers reviewed 1,935 government Web sites from June through August.
The researchers ranked Taiwan, Singapore, the United States, Canada and Monaco as the top five, followed by China and Australia.
The study's authors say well-developed government Web sites help users explore and learn about the country.
"Citizens love the convenience of 24-7 government. They like being able to go to a Web site and download a report or check out a database," West said. He added that more governments are offering constituent services online.
The rankings were based on two dozen criteria, including the availability of publications, databases, disability access, privacy, security and the number of online services.
Last in the rankings was Tuvalu, a tiny island nation in the Pacific, which has generated revenue by selling its coveted ".tv" Internet domain. Located midway between Hawaii and Australia, the islands' exports historically have been coconut oil and postage stamps.
"Each time we go to their site, it seems to have been overtaken by a commercial entity," West said.
Overall, the research team found 89 percent of Web sites have online publications and 62 percent have links to databases. Just 14 percent show privacy policies, and 8 percent have security policies.
The study found government Web sites lagging on providing access for the disabled, with just 14 percent of sites providing some form of disability access, such as assistance for the vision or hearing-impaired. That percentage did not increase from the previous year.
West said the relatively small percentage of sites considered friendly to the disabled appears to be due to the fact that "not all nations see this as a top priority."
He said the solution is a public education campaign about the need to make online government universally accessible.