Production of staples occupies an important part in Sub-Saharan Africa‘s crop production, and maize is its single most important food staple. This thesis mainly examines the role of maize in farmers‘ livelihoods and wellbeing in Tanzania, in the context of a long period of reforms that have affected both the maize market, agriculture more widely. It does so by exploring the role of maize in household‘s on and off-farm diversification, the determinants of crop productivity, and the relationship between diversification, commercialisation and‘ well-being. A number of specific issues are explored including the importance of factors such as farm size and education, access to key inputs such as seeds, fertilizers and agricultural extension services. The thesis uses data collected from three districts of Rukwa, one of Tanzania‘s major maize producing regions, and some secondary agricultural data from official sources. The research found that households with more land were generally more diversified (both on-farm and off-farm) than those with less land, and they experienced higher levels of well-being as measured by a range of concepts of well-being, but that maize continues to play an important role households‘ livelihoods and well-being. The research also revealed low levels of use of important agricultural inputs such as modern fertilizers and extension services, which may explain the low yields observed in the region. Education emerged as an important factor in raising yields, increasing commercialisation and also well-being, suggesting that nonagriculture policies may also be important for improving productivity and welfare of farmers. Despite the importance of crop production to their‘ well-being, households face several constraints; these include access to fertilizers, improved seeds and other chemical inputs necessary for higher production, and extension services. These findings have important policy implications as many rural households continue to rely on agriculture, especially production of staples. Therefore, these results could help the central and local governments to formulate strategies geared towards improving rural well-being.