Substance abuse among public secondary school students is reality that is spreading at an alarming rate. If not checked, it could destroy the youth who are in their formative stage in life. Its outcomes include school dropouts, injuries, loss of lives, destruction of properties, moral decadence, misallocation of resources, indiscipline and compromised academic standards. According to the findings of a study conducted in 2005 on substance abuse in five major cities in Kenya, Kisumu and Nakuru lead the rest of the major cities and towns in the country in the prevalence of substance abuse. The study established that the factors that influence students most into substance abuse were peer pressure, media influence, frustrations and copying of idols. Alcohol, Cigarettes, Miraa/Khat and Marijuana were found to be the most commonly abused substances in dealing with substance abuse among students. The three strategies used most frequently by managers of public secondary schools were; use of professional counsellors, teachings on substance abuse, and training of peer educators while challenges encountered by managers of public secondary schools (principals, deputy principals and heads of departments) were found to be the rehabilitation of substance abusers, reducing the prevalence of substance abuse, and improving the performance of substance abusers. The study’s recommendations were that a comprehensive curriculum on substance abuse be introduced in schools, areas around the schools should be made as drug free as possible, the education of students on substance abuse should start in primary schools, the Teachers’ Service Commission should post full time professional counsellors to public secondary schools, and the government should establish free rehabilitation centres to cater for students who are substance abusers. The findings of this study are significant to the managers of public secondary schools in Kisumu East Sub County because it may help them to better understand the issues related to substance abuse among students in their schools and to come up with effective strategies to be used in addressing substance abuse related issues. It is significant to educational planners and economists whose concerns are optimal utilization of inputs and outputs for efficiency of educational systems.