This research explored the viewpoints of 116 religious leaders in Sierra Leone including 32 Muslims and 84 Christians from nine different denominations. The study’s primary objectives were to understand their perspectives on family planning, modern contraceptives, sexual reproductive health education, and the religious doctrines influencing these beliefs. The study also aimed to gauge their knowledge of family planning and modern contraceptive methods.In September 2021, data was collected from religious figures purposefully selected from 11 districts and the Western Area Urban through 16 focus group discussions. The discussions, initially conducted in local languages, were translated and transcribed into English. The data was then subjected to a thematic analysis using NVIVO 12 software.The analysis revealed diverse opinions, both across different religions and within specific denominations. A common thread was the general support from both Christian and Muslim leaders for natural birth spacing methods, with some reservations about artificial techniques. There were clear distinctions in beliefs among denominations: Catholics largely considered artificial contraceptives to be against the divine will, while Pentecostals and some Muslims found them permissible under certain conditions.The findings underscore the potential of religious leaders in Sierra Leone to act as influential advocates for family planning, given their support for natural birth spacing. To maximize the impact of advocacy efforts, the study suggests a focus on engaging Pentecostals and Muslim leaders rather than Catholics. Additionally, religious leaders with professional backgrounds in health or education appear more receptive to modern contraceptive methods and could be particularly valuable allies in these endeavours.