Abstract The aim of this study was to investigate on the effect of drug abuse on the students’ behaviour in both government and community secondary schools in Uganda. The study was guided by the following objectives; to investigate the causes of drug abuse among secondary students in Nsangi Town Council, to establish the effects of drug abuse on the behaviour of students in Nsangi Town Council and to determine the possible remedies to the problems of drug abuse among secondary students in Nsangi Town Council. This study also employed descriptive survey research design. The target population for this study consisted of all five (5) secondary schools comprising of five head teachers, ten (10) teachers, ten(10) BOG members and one hundred (100) students who were selected using systematic sampling and simple random sampling. The sample size was 125 respondents. The data collection tools for this study were questionnaires, interview guides used to assess the validity and reliability of the research instruments. The data was analyzed quantitatively guided by the research objectives. The researcher used statistical package for social science (SPSS) to analyze the data. The results were presented as per the research questions. The study established that the causes of drug abuse among students were weak legislation and law enforcement, lack of moral learning standard, deteriorating morality, degraded methods of punishment, low parental involvement in education and failure of school system. These results into falling standard of education, destruction of school property, high school dropout, poor academic performance, interruption from sleep, study and humiliation of other colleagues. The researcher recommends that; the government should put in place the strategies that can prompt stakeholders in providing partici~patory support and help in protecting young people from drug abuse; there is need for affirmative policy formulation to provide use of students friendly disciplinary measures like guidance and counselling as a subject in the teachers training curriculum in order to produce professional teachers counsellors, public awareness through education or sensitization on the dangers of drug abuse, reinforcement of government policies and programme to strengthen the administration and management of the schools.