This study is based on a study undertaken to assess how ecotourism has influenced biodiversity conservation in Jozani–Chwaka Bay National Park (JCBNP). It involved two communities surrounding the park, namely Pete and Kitogani. Field data were collected using structured questionnaires, key informant interviews and field observations. Questionnaires were administered to 76 households, whereas key informant interviews were conducted with foresters and JCBNP officials. Data analysis was undertaken using standard statistical methods. Findings from the study show that biodiversity management in the JCBNP has improved considerably after the introduction of ecotourism. The number of endemic colobus monkeys (Piliocolobus kirkii) and other rare species has increased. However, this achievement has been attained by restricting surrounding communities from using forest resources without providing alternative sources of livelihood. Findings also show that the benefits from ecotourism do not reach individual households, but the community as whole, in form of various social services. This has caused some resentment among the local people leading to their reluctance to reduce their direct use of ecosystem services available in the JCBNP, claiming that they cannot sustain their livelihood without such services. This has become a major source of conflict between the JCBNP and surrounding communities. Increased awareness and knowledge on biodiversity conservation would be needed for the communities surrounding the park to realize the potential and long-term benefits of ecotourism, and hence the need for their increased involvement in biodiversity management.