Drug abuse is becoming increasingly problematic in Kenya. Studies done outside Vihiga and Sabatia Sub-counties have shown that students abuse drugs. The foremost concern was the number of these students that would form an addiction to serious substances, jeopardizing their own health and safety and creating difficulties for their families and the public at large. Preliminary survey in five schools revealed that students in Vihiga and Sabatia sub-counties were abusing drugs. In Vihiga and Sabatia sub-counties, cases of indiscipline had been experienced. For instance, 4(80%) were found doing examination under the influence of alcohol, 4(80%) stealing and 5(100%) students fighting. It was alleged that most of these incidences involved students who abused drugs. What was not known was the influence of drug abuse on student discipline in secondary schools in Vihiga county. The objective of the study was to establish the influence of drug abuse on student sexual harassment in secondary schools in Vihiga county. A conceptual framework showing influence of drug abuse on student sexual harassment in secondary schools was used to guide the study. The study established that with regard to influence of drug abuse on student sexual harassment principals' rating was moderate (M =3.04) while Guidanceand Counselling teachers' was high (M = 3.61). The findings of this study are useful to the managers of schools in Kenya in understanding the issues related to substance abuse among students in their schools and to come up with strategies to be used in addressing substance abuse related issues.