This study assessed the levels of teachers’ collaboration practices in public primary schools in Tanzania. The study employed a convergent mixed design within the framework of a mixed research approach in the Ilemela and Misungwi district councils in the Mwanza region, Tanzania. The study was anchored in the Social Constructivism theory, which guided it. From a population of 2994 teachers in 218 primary schools, Yamane’s formula yielded a sample size of 352 that included ordinary, academic and head teachers and the key informants. Respondents were chosen from 44 schools in two districts to ensure that the study’s sample was both proportional and representative. Questionnaire, interview and documentary review were used in data collection. The quantitative data were analysed descriptively in terms of mean, standard deviation and skewness, while the qualitative data were analysed through content analysis. The study found that the levels of teachers’ collaboration were high. The study recommends the government to review and re-balance the work force as a strategic mechanism to offload teachers shouldering more teaching load than the recommended workload.