Land Use Conflicts (LUCs) over resource use are ever increasing in Tanzania. This happen inspite of several government and non-government efforts to contain them and their socio-economic impacts. The conflicts have adverse impacts on the gender roles of farmers and agro-pastoralists. This paper analyses the causes and impact of the persistent land use conflicts on gender roles in Kilosa and Mvomero Districts. The study from which this paper is based adopted a cross-sectional research design and involved 124 respondents. Structured questionnaires and checklist for key informants were the main tools for data collection. Descriptive statistical analysis was employed to establish the characteristics of the study sample. Binary logistic regression was used to estimate the predictor variables for the land use conflicts. The findings indicate that there were changes in gender roles in participation to some activities such as land preparation for cultivation, spraying pesticides, watering crops, looking after livestock and treating sick animals. Sex, residence status, human and livestock population pressure were important predictors for land use conflicts (p<0.05). It is concluded that LUCs are contributed by population pressure of both human and livestock in the light of declining land resources, and lack of security of land tenure to farmers and agro-pastoralists. In view of the findings, it is recommended that the government and non-governmental organisations should assist farmers and agro-pastoralists to develop and implement gendered land use plans to help peaceful co-existence and sharing of resources between farmers and agro-pastoralists