This study sought to examine factors contributing to teacher absenteeism in public primary schools in Nyamagana District Mwanza Region in Tanzania. It was guided by the following research questions: What are the factors contributing to teacher absenteeism in public primary schools in Nyamagana District? What are the effects of teacher absenteeism in public primary schools in Nyamagana District? What are the possible strategies to mitigate the problem of teacher absenteeism in public primary schools in Nyamagana District? This study was anchored on Adams’ Equity theory of motivation. A mixed research approach and convergent parallel mixed research design was employed. Participants were drawn from four public primary schools located in Nyamagana District. A sample of 56 pupils, 40 teachers, 3 head teachers and 1 Teachers Service Commission Officer were involved in the study. Data was collected through questionnaires, in-depth interview and document analysis. Questionnaires had a Cronbach Alpha Coefficient of α = 0.733 signifying that the instruments were reliable. Quantitative data from questionnaires was analyzed through descriptive statistics basically frequencies and percentages, the Statistical Package for Social Sciences Version 20 was used in this case. Thematic analysis was employed in the analysis of qualitative data. The study found that health problems, family responsibility and other official roles assigned to teachers contributed to teacher absenteeism. Poor academic performance, poor coverage of syllabus and pupils’ misconducts were the most prevalent effects of teacher absenteeism. Recommendations are made for critical interventions by government leaders, policymakers and educational leaders to support teachers through improved working environment and ensuring that directive teachings and seminars on laws, rules and regulations governing teachers’ service are provided at school level to create awareness among teachers on the respective legal framework.