ABSTRACT Drug and substance abuse threatens and tends to derail these noble strides by demotivating the students in learning and subsequently ruining school going children that the government intends to rely on in driving the economy to the next level. Despite the overwhelming intervention strategies by the Government, religious organizations, non-state actors and many other keen stakeholders to curb the problem of drug and substance abuse especially among the youth, the number of school going youth being suck into drug abuse seems to be escalating day by day. The purpose of this study was to assess the effect of drug and substance abuse on participation in learning among secondary school students in Bunyangabu District in Uganda. The study used descriptive survey design combining both qualitative and quantitative research strategies. The research targeted all the form three students and their respective school principals in the 12 secondary schools in Bunyangabu District, six schools constituting 30% of the 12 schools in Bunyangabu District were sampled. Purposive sampling was used in the selection of the nine schools and their respective principals. From each selected school, 20 Form three students were selected using systematic sampling. Questionnaires were used for data collection. Once data was obtained from the field it was coded and analyzed by computer using a statistical software SPSS (Statistical Package for Social Sciences). On basis of the findings, the study concludes that all the principals had experienced cases of drug abuse by students in their schools. Majority of the principals (60.5%) kept records of those students engaging in drug abuse. The study concluded that most of the schools offered guidance and counseling to the students and that most of the students had attended guidance and counseling against drugs in their schools. Alcohol was the frequently abused drug in the schools as expressed with a mean of 2.632. The study concluded that drug abuse among the students caused dropping out of school, strained relationship with other students, lack of interest in studying, low concentration span and declining grades. The study concluded that anxiety, headache, feeling sleepy, confusion and vomiting were serious effects of drug abuse among students and that the students have friends who take drugs. The study recommends that all schools should set up guidance and counseling offices facilitated by professionals to counsel students who indulge in drug abuse. Parents and teachers should discourage students and be firm in ensuring that the students do not take alcohol which is the most abused in the schools. The parents should also ensure they do not give so much money to their children and if they do so they should ensure that the money is put into constructive use.