Britain and Canada have also said they would not sign the treaty after negotiations ended at the U.N. International Telecommunications Union conference in Dubai, The Hill reported Thursday.
The three countries have voiced opposition to a treaty resolution that would see a U.N. agency given more control over future Internet policy discussions.
"It's with a heavy heart and a sense of missed opportunities that the United States must communicate that it's not able to sign the agreement in the current form," Terry Kramer, the U.S. ambassador to the conference, said.
The United States says it wants any mention of the Internet removed from a treaty, warning some ITU member states could censor the Web under the auspices of security.
The United States, Britain and Canada have said they're against calls for all states to have equal rights to the governance of the Internet.
Any treaty proposed by the ITU should restrict itself to regulation of telecommunications only, Kramer said.
"The Internet has given the world unimaginable economic and social benefit during these past 24 years."
"Keeping to the pure focus of this conference, [which is] advancing broadband in a telecom arena, is the right approach," he said last week.