Jewish atheism refers to the atheism of people who are ethnically and (at least to some extent) culturally Jewish. Contrary to popular belief, the term "Jewish atheism" is not a contradiction because Jewish identity encompasses not only religious components, but also ethnic and cultural ones. Jewish law's emphasis on descent through the mother means that even religiously conservative Orthodox Jewish authorities would accept an atheist born to a Jewish mother as fully Jewish.

Jewish secularism, which describes Jews who do not explicitly reject the existence of God but also do not believe it is an important part of their Jewishness, has a long tradition in the United States. A 2013 study conducted by the Pew Research Center found that 62% of self-described American Jews say being Jewish is mainly a matter of ancestry and culture, while just 15% say it is mainly a matter of religion. Even among Jews by religion, 55% say being Jewish is mainly a matter of ancestry and culture, while 66% say it is not necessary to believe in God to be Jewish.