Around 100 people protested outside the company's offices in California, urging it to reverse proposals made with telecom giant Verizon to treat fixed-line services differently to wireless and some specialised content.
The move would allow internet service providers to give priority to certain online traffic, which could disadvantage smaller businesses and individuals.
Google previously had been a champion of policies such as net neutrality - the principle that keeps the internet open and free from discrimination. Its decision to team up with Verizon, long an opponent of such policies, has drawn the ire of public interest advocates, said media campaign group Free Press.
James Rucker, executive director of civic action group ColorofChange.org, said, "Those here today represent more than 300,000 people around the country who are publicly calling on Google not to turn its back on the platform and community that enabled it to thrive in the first place. We have seen what happens when big industry is able to write its own rules - look at the banks, look at BP. We cannot let the same happen with the internet."
In a blog post Google said it has been the leading corporate voice on the issue of network neutrality over the past five years and the policy proposals it drafted with Verizon would lock in key enforceable protections for consumers.
Telecoms company AT&T has given its backing to the plan, but Facebook and Skype have denounced it.
ColorofChange.org petitions US Federal Communications Commission
ColofofChange.org is petitioning FCC chairman Julius Genachowski on the issue of net neutrality. On its website, the group states, "Our communities rely on the internet to speak without a corporate filter, and to be able to organise and hold public officials and corporations accountable. But if these companies succeed, a few major corporations would control which voices are heard most easily, and it would be much harder for grassroots groups, individuals, and small businesses to compete with large corporations and well-funded special interests. "