ABSTRACT The aim of this study was to investigate the relationship between secondary schools environment and students’ indiscipline in secondary schools in Nyamagana district, Tanzania. The objectives were to examine the school environment in secondary schools in Nyamagana district, Tanzania; to assess the level of the students’ indiscipline in secondary schools in Nyamagana district, Tanzania; and to establish the relationships between school environment and students’ indiscipline in secondary schools in Nyamagana district, Tanzania. The sample size of the study was 357 respondents derived from the total population of 858 (2017) including 727 students and 131 teachers for the purpose of the study. Frequency and percentage distribution were used to determine profile of the respondents. Data were collected through questionnaire and observation to gather information. Quantitative data were analyzed using SPSS (Statistical Package for Social Sciences) 16.0 version. The study achieved the response rate of 92.99%. The major findings of the study revealed that, a significant and positive relationship (r = 0.513, N = 332, p = 0.0001 < 0.01 < 0.05) between school environment and students’ indiscipline in Nyamagana district, Tanzania.The study recommended that, the government of the united republic of Tanzania should collaborate with its communities in providing an enabling environment conducive for teaching and learning through adequate facilities such as school plants and facilities, reading material such as books, journals, newspapers and other instructional facilities so as to facilitate the learning processes and keep the students busy. Head teachers should ensure that teachers adopt an effective classroom management and teaching methods within an organized classrooms; Government should made available special offices for guidance and counseling in secondary schools as well as to establish rules and regulation in guiding the students on does and don’t within the schools in order to reduce indiscipline cases among the students in secondary schools in Nyamagana, Tanzania. School heads should also make sure that disciplinary actions are taken on students who areinvolved in truancy or other related offences so as to improve their performance and positive behaviors.