Taxation Institute of Hong Kong
- Seeking to promote the study and the exchange of information and views on taxation.
- http://www.tihk.org.hk/

Tax Foundation
- Devoted to educating taxpayers about tax policy and the total tax burden borne by Americans at all levels of government.
- http://www.taxfoundation.org/

Robert D. Burch Center for Tax Policy and Public Finance
- Established at the University of California, Berkeley, to promote research in tax policy and public finance.
- http://emlab.berkeley.edu/users/burch/index.html

Geonomy Society
- Educational nonprofit offering news, commentary and analysis on the relationship between economics and sustainability.
- http://www.progress.org/geonomy/

Alabama Arise
- Advocating a progressive taxation system for the state.
- http://www.alarise.org/

Institute for Local Self-Reliance
- Article advocating heavy taxes on natural resources, such as coal, on the theory that this will reduce pollution.
- http://www.ilsr.org/

PETA - Tax Meat!
- Proposing an excise tax on meat, on the belief that such a tax will benefit public health and the environment.
- http://www.taxmeat.com/

Henry George Institute
- Advocating the application of economic principles to local and international problems, and proposing the replacement of all income taxes with real estate taxes.
- http://www.henrygeorge.org/

Center on Budget and Policy Priorities
- Public policy advocacy organization specializing in federal budget issues from a low-income perspective.
- http://www.cbpp.org/

Tennesseans for Fair Taxation
- Dedicated to creating a fair, progressive tax system that meets the state's financial needs.
- http://www.yourtax.org/

Massachusetts Budget and Policy Center
- Statewide organization dedicated to advocating for tax fairness, economic justice, and socially responsible budgeting.
- http://www.massbudget.org/

Banneker Center for Economic Justice
- Essays, mailing list, and forum, questioning leading 'tax reform' proposals.
- http://www.progress.org/banneker/

Citizens for a Sound Economy
- Advocates market-based solutions to public policy problems.
- http://www.cse.org/

CapitolWatch
- Advocating for tax reduction, and acting as a watchdog against perceived wasteful government spending.
- http://www.capitolwatch.org

California Tax Reform Association
- Non-profit organization advocating for state tax relief efforts and spending limits on government.
- http://www.caltaxreform.org

Institute on Taxation and Economic Policy
- Non-profit research group performing analysis, fostering debate, and educating the public on federal, state and local tax policy.
- http://www.ctj.org/itep/

National Taxpayers Union
- National taxpayer organization, lobbying Congress and state legislatures, and engaging in media activism in relation to tax issues.
- http://www.ntu.org/

Canadian Taxpayers Federation
- Advocating for reductions in business tax and regulation, and increased transparency in the expenditure of tax revenues.
- http://www.taxpayer.com/

Citizens for Tax Justice
- Non-profit research and advocacy group focusing on federal, state and local tax policy.
- http://www.ctj.org

Canadian Tax Foundation
- Independent, non-profit tax research organization analysing personal, corporate, and international tax and government finance matters.
- http://www.ctf.ca/

Americans for Tax Reform
- Advocating for a national, single rate, flat income tax.
- http://www.atr.org