Grassroots lobbying, or indirect lobbying, is lobbying with the intention of reaching the legislature and making a difference in the decision-making process. Grassroots lobbying is an approach that separates itself from direct lobbying through the act of asking the general public to contact legislators and government officials concerning the issue at hand, as opposed to conveying the message to the legislators directly. Companies, associations and citizens are increasingly partaking in grassroots lobbying as an attempt to influence a change in legislation.

The unique characteristic of grassroots lobbying, in contrast to other forms of lobbying, is that it involves stimulating the politics of specific communities. This type of lobbying is different from the more commonly known direct lobbying, as it is naturally brought upon by the organization.

There are several tactics used by groups in order to promote or advocate different issues politically, but the main two tactics used in grassroots or "outside" advocacy are education of constituents through holding press conferences or organizing press releases, and mobilizing targeted people who will be impacted negatively or positively to create a movement.

Grassroots lobbying often implement the use of media to expand their outreach. Campaigns are developed and are published in all forms of media ranging from television to magazines and internet. Because grassroots lobbying is geared toward local organizations and communities, these types of media outlets are used mainly by large associations that can afford them. Smaller organizations tend to use free media on public television, radio and other smaller outlets. Other forms of free media that make a large impact are things like boycotting, protesting and demonstrations.

The trend of the past decade has been the use of social media outlets to reach people across the globe. Social media are by nature grassroots organizers. They provide a way for communities, not only to interact, but to form around topics. Implementing social media tactics in grassroots lobbying would provide a much broader outreach and would allow activists to not only inform but interact with various people about their cause.

Some advocates are now using social media to reduce the cost of traditional campaigns, and to more precisely target public officials with political messages.

An example of the use of social media as a tool of grassroots lobbying is in the Black Lives Matter movement. Social media created platforms for broad discourse that allowed for the information sharing of both policy issues and solutions as well as mobilization. In interviews conducted by Mundt and Ross, social media administrators for BLM groups emphasized the importance of promoting action plans for members on social media to achieve concrete results. These action plans include grassroots lobbying in the form of directly contacting legislators about policy reform.

Another example is Urban Legend, a Virginia-based startup launched in 2020 by former Trump administration staffers that recruited social media influencers including makeup artists, Nascar drivers, home improvement gurus, mommy bloggers, NFL athletes and Olympians.