All of the Saudi citizens of Unaizah are Sunni Muslim with a small minority of Dharmic religions, (mostly Hinduism) brought and practiced in the city by Asian workers (mainly Indians). As the rest of Saudi Arabian cities, non-Islamic worship houses are not allowed.
The majority of the city's inhabitants are socially conservative. One of Saudi Arabia's leading religious clerics Muhammad ibn al Uthaymeen was a student of the late Sheikh Abd ar-Rahman ibn Nasir as-Sa'di, an Unaizah native. Muhammad ibn al Uthaymeen himself was born and raised in Unaizah. He lived in Unaizah until he died, where many mosques have been built and named after him