This study is based on the assumption that the religious beliefs of decision-making family members are effective in the formation of organizational spirituality in family businesses. Family businesses, as a value-oriented business structure, offer a wide area for religious beliefs to influence decisions. The main purpose of the study is to determine whether the religious beliefs of decision-making family members influence the formation of organizational spirituality in family businesses. In line with the main purpose of the research, a case study was conducted with different generations of family members and professional managers of a family business with a history of 70 years. Questions asked of the business partners and managers who participated in the interview examined how religious belief affects business practices. According to the results obtained, the results showed that the ways family members are raised, the way they relate to each other, and decision-making processes are affected by religious belief. It was concluded that a spiritual environment is provided in the business, and this is formed thanks to the religious beliefs of the family members.