Judaism isn't a religion.
You may have heard people refer to themselves or others as "religious jews" but that is a term that only really exists in Israel. A more correct term would be practicing jews. Here is an explanation based on things said by Rudy Rochman: Judaism is not a religion. Let's compare it to other religions: In Christianity if you don't believe in Jesus and his teachings, you are not a Christian. In Islam if you don't believe in the Quran, Surrahs and Muhammad as the last and most important prophet of God, you are not a Muslim. In Buddhism if you don't believe in Buddha and his teachings, you are not a Buddhist. But in Judaism you could be atheist, agnostic or even anti "religious" and you are still a Jew. The definition of religion is: (1) : the service and worship of God or the supernatural. (2) : commitment or devotion to religious faith or observance. A Jewish person can have no connection to those and still be a Jew. So what is "Judaism"? ...