In Tanzania fertility rate is still high as population is growing at a rate of 2.7% per annum. The major objective of this study was to examine the influence of socio-cultural factors on fertility among women in Arusha district. A cross-sectional descriptive study design was adopted and four villages were selected. From each village 18 respondents with at least 3 children were randomly selected making a total of 72. Also 2 health facilities and 8 health care personnel were purposively selected. Data collection was done by distributing questionnaires to the selected members of the communities and interview was conducted with selected key informants from the health facilities. Quantitative data were analyzed using descriptive statistics and data presented by text and Tables to illustrate findings. Qualitative data were analyzed using thematic method and presented by themes. The findings indicated that out of the 72 respondents 43.1% and 40.7% were 36-45 and 26-35 years respectively, 63.9% had attained primary school education and 11.1% were those who had no formal education. Also about 37.5% of the respondents had 5 children, and 61% of them desired to have more children in future. 30.9% of the respondents married at the age of 14 - 19 years, 36% of the respondents preferred sons than daughters, and also 77% of the respondents said that males did not attend clinics with their wives. Therefore for attaining lower fertility rates in the study area, more education is needed to be provided in the community on the importance of family planning and discourage cultures which influence high fertility such as early marriage and sex preference. There is also a need to restructure the family planning services to involve males so as to expand the utilization of these methods by both women and men.