Tanzania is among the few countries in the world endowed with vast range of tourist attractions. The tourism industry is Tanzania’s greatest success story since the introduction of free market economy in 1990s. Despite its impressive recent economic performance, Tanzania remains a poor country. The purpose of this study was therefore to assess the effects of tourism investments on poverty reduction in rural communities in Serengeti district. The specific objectives were to: identify types of tourism investments; examine the effects of tourism investments; and determine the potential tourism development investments. Data were collected from 124 respondents, including 100 community members household heads and 24 key informants using questionnaires, researcher’s diary and checklist. Quantitative data were analysed by using SPSS computer software and “content analysis technique” was used to analyse qualitative data. The study identified different types of tourism investments in rural communities in the study area, their effects on poverty reduction, and potential for tourism investments development. It was concluded that: employment opportunities for rural communities were low in cadres with skills and remuneration; local people have complex livelihoods strategies which are affected by tourism in various ways; and there is a clear opportunity to have significantly their benefits from tourism. Thus, it was recommended that in order to increase tourism effects on poverty reduction, there is a need to institute training programmmes that would ultimately provide chance for rural communities to be employed in high cadres with high pay; rural communities to have considerable role in decision making; and the community to integrate its marketing and products strategies to take the best advantage of existing tourism opportunities. Areas for further research are also suggested.