Background The prime concern of a society is to ensure healthy growth and development particularly of students of primary school because they are the future of the nation. Normal growth and development takes place only if there is optimum nutrition and safe environment to live in. The World Health Organization estimates that there are 178 million children that are malnourished across the globe and malnutrition contributes to the deaths of over one half of children in developing countries and Tanzania included. Methodology Analytical cross‐sectional study was conducted among 914 students in Ulanga district. A multistage cluster sampling technique was applied, then a school to school survey was performed for the selected school, anthropometric measurements of primary school students for sampled schools were done and the body mass index was calculated to assess the nutritional status of primary school students. Environmental factors were studied and correlated with nutritional status. Results A total of 82.7%, 16.7%, 0.3%, and 0.3% of students were found to be underweight, normal overweight and obese respectively. Significant association was observed between nutritional status and unsafe water, poor method of water purification specifically filtration, personal hygiene and high house status and majority of students were underweight. Conclusion and Recommendation Unsafe water, poor method of water purification, personal hygiene and high house status are related to nutritional status and majority of students were underweight. Proper sanitation of the drinking water should be promoted in the community to prevent water borne diseases in the children, mass education on person hygiene and proper method of water purification should be promoted.