Several different actors are involved in making sure smallholder farmers are motivated to commit funds in expectation of future returns (investment decisions) from useful domesticated animals (livestock). However, efforts by the government, international organizations and the private sector have not been able to significantly increase trade trends in Tanzania’s livestock which explains that there could be a lot more reasons for that. This manuscript assesses the socio-cultural factors (SCFs) influencing livestock investment decisions among smallholder farmers in Mbulu and Bariadi districts in Tanzania. A cross-sectional research design was employed where a sample of 333 respondents and 9 key informants were interviewed. Primary data were collected using a structured questionnaire and a key informant checklist. A binary logistic regression model (BLRM) was used to analyse the relationship between SCFs and livestock investment decisions. Results show that store of wealth is the most influencing factor followed by prestige, bride prices, ethnicity and number of children (significant at p < 0.05) to household livestock investment decisions. The study generally concludes that smallholder farmers consider their cultural perspectives before they decide on livestock management styles and that blending the SCFs and other factors could secure more livestock investments.