Sociological and economic bargaining theories have different predictions on how women's economic status - primarily women's employment - affects their risk of partner violence. These competing predictions were mirrored in a systematic review of published evidence from low and middle income countries. Increasingly researchers from North America and Europe are highlighting that there exists different forms of partner violence, and that the relationship with women's economic status may not be the same depending on the form. Currently there is limited in-depth exploration of the forms of partner violence and their relationship with women's economic status in sub-Saharan Africa. This thesis fills this gap in knowledge by exploring this relationship in two contrasting Tanzania settings: Dar es Salaam and Mbeya. An existing household survey data and primary qualitative interviews with women market traders were analysed. This study found that partner violence broadly divided into three groups that did not differ by study setting: moderate physical violence; sexual dominance; and severe abuse. Women who experienced severe abuse were most likely to have experienced high intensity emotional aggression, controlling behaviour, poorer health outcomes, and to have sought help. While there was no compelling evidence on the relationship between women's economic status and partner violence in Mbeya, there was suggestive evidence of an increased risk in Dar es Salaam. In both sites, partners' 'refusal to give their wives money' was the single most predictive risk factor of partner violence. Qualitative interviews found that men's insufficient financial provision for the household was a strong motive for women to enter into paid employment, and in doing so, mitigated one major source of conflict in the household - negotiating over money. This thesis also sheds light on the limitations of current sociological and economic bargaining theories, suggests future research priorities, and discusses the implications for women's economic empowerment programmes.