Saturninus of Cagliari was a Christian bishop and martyr who lived in Cagliari during the late third and early fourth centuries. According to religious tradition, he was executed in his home city following an order issued by the governor Barbarus. He is remembered as a martyr for refusing to participate in sacrifices to Jupiter during the persecutions led by Diocletian. While historical interpretations vary regarding the specific details of his life, he remains a central figure in the religious history of Sardinia.