Cash crops such as coffee, cotton, and tea have been an important income for farmers especially smallholder farmers in the Sub-Sahara Africa (SSA). However, many farmers started to turn in to new cash crops with higher market prices. Vanilla (planifolia) is one of such alternative cash crops which has been attracting more and more smallholder farmers in Tanzania in the past three decades. This study explored vanilla and its sustainability in Tanzania using a Sustainability Opportunity Study (SOS) approach. The aim of this study is to research whether vanilla could bring new opportunities on poverty reduction for smallholders in the SSA. The thesis selected Kagera region in Tanzania as the case study area for being the first and leading vanilla production region in the country. Key stakeholders and their sustainable impacts such as the farmers’ cooperative Maendeleo Ya Wakulima (Mayawa) have been identified. Sustainable vanilla production in Tanzania is defined as generating maximal economic profits for the main stakeholders with minimal harm to the society and the environment. Results illustrate that vanilla is beneficial for smallholder farmers in many ways. However, it is currently not sustainable with a huge gap between the current performance and potential performance for key stakeholders. Both smallholder farmers and Mayawa have the improvement potentials for more income. The opportunity is there but with several serious challenges such as price fluctuations, climate change, smuggling, lacking stable market, and so on. Vanilla farmers cannot stop farming vanilla even when facing an unstable market. This study suggests that smallholder farmers and Mayawa must work together for a sustainable development of vanilla production in Tanzania.