Alba was raised as a Roman Catholic and still considers herself "spiritual". In her adolescence, she became a born-again Christian, but left the church after four years because she felt she was being judged for her appearance, explaining:

Alba also had objections to the church's condemnations of premarital sex and homosexuality, and the lack of strong female role models in the Bible, explaining "I thought it was a nice guide, but it certainly wasn't how I was going to live my life." However, she has stated that she still holds her belief in God despite leaving the church.

As the daughter of religiously conservative parents, Alba, whose grandparents did not allow her to wear a bathing suit around the house, maintains a no-nudity clause in her contract, though she has claimed she had been open to the possibility of appearing nude in Sin City. She remarked of a GQ shoot in which she was scantily clad, "They didn't want me to wear the granny panties, but I said, 'If I'm