These resources are specific to atheism.  Please contact us if there's a resource that you think should be included here.

American Atheists (AA)
https://www.atheists.org/

American Atheists, Inc., is a nonprofit, nonpolitical, educational organization dedicated to the complete and absolute separation of state and church, accepting the explanation of Thomas Jefferson that the First Amendment to the Constitution of the United States was meant to create a "wall of separation" between state and church.

Atheist Alliance International (AAI)
https://www.atheistalliance.org/

Atheist Alliance International is a global federation of atheist groups and individuals committed to educating its members and the public about atheism, secularism, and related issues, and supporting atheists around the world who are excluded, disparaged, discriminated against, and criminalized.  AAI, which serves as a positive voice for atheism and secularism, was also granted UN Special Consultative status in 2013.

Atheist Experience, The (AXP)
http://www.atheist-experience.org/

The Atheist Experience is a weekly internet television show based in Austin, Texas, USA, that is geared at a non-atheist audience.  Every week hosts field live calls from atheists and believers alike, and sometimes it can get quite feisty.  (The Atheist Experience is produced by the Atheist Community of Austin.)

Atheist Frontier - Questioning what's Real
https://www.atheistfrontier.com/

The Atheist Frontier provides information about atheism, and encourages the skeptical examination and discussion of science and technology, critical thinking, philosophy, life, history, cross-cultural ethics and morals, social-economic and political systems, and much more.

Canadian atheists (Ca) - True, Northern, Strong, and Free
https://www.canadianatheists.ca/

The Canadian atheists are the national atheism group for Canada, and they are concerned about rights, freedoms, and the general well-being of atheists both in Canada and internationally.  One of their core desires is for peaceful advocacy, and they are happy to participate in public discourse as a means of engaging in the free exchange of ideas.

Definitions of "atheism" and "atheist" - Clarifying a natural classification
https://www.define-atheism.com/

This is an entire web site that is solely dedicated to providing the proper definitions of the words "atheism" and "atheist" as the natural classification of "absence of belief in deities."  Strong support from linguistic structure, etymology, and logic are explained and demonstrated, and included for good measure are dictionary, encyclopedic, videographic, and academic references.

International Association of Atheists (IAA)
https://www.internationalatheists.org/

The International Association of Atheists is a global non-profit that takes on tough issues like human rights, bringing evidence-based education to theocratic countries, ending blasphemy laws, and supporting atheists in danger.  The IAA envisions a future in which atheists have the opportunities and resources they need to participate openly and confidently in every aspect of society.

Talk Heathen - We're kind of a big deal...
https://www.talkheathen.com/

Talk Heathen is a weekly live call-in television show in Austin, Texas, U.S.A. that is geared toward long-form and on-going dialogue with theists & atheists about religion, theism, and secularism.  (Talk Heathen is produced by the Atheist Community of Austin.)