Bill Maher was born a Jewish mother and a Catholic father. As an adult, Maher has not known to actively practice either Judaism or Catholicism in any meaningful religious sense. Maher is widely regarded as a deist, as he has expressed belief in God, but he believes that God does not answer prayer or interact with humanity.
Bill Maher is a Vegan. Ethical Veganism is a religion, but Veganism does not function as a religion for all vegans. At this point we do not yet know if Maher is an Ethical Vegan or a lifestyle-only vegan.
Bill Maher has made a career out of talking about topics that are often considered off-limits, including the topic of religion. His views have been wide-ranging. He has often made statements strongly in support of various spiritual and religious values and beliefs, while at the same time he has been highly critical of many aspects of organized religion.
One of Bill Maher's favorite causes is lampooning so-called "political correctness," which he derides as being forcibly maintained dishonesty and cynicism masquerading as politeness and tolerance.