The study investigated the effect of health education intervention on knowledge about alcohol among senior secondary school adolescents in Eleme, Nigeria. The study was guided by three research questions and two null hypotheses tested at 0.05 alpha level. The research design was a pre-test post-test quasi experimental research design. A sample of 817 senior secondary school adolescents were selected from 3,750 adolescent students in 5 senior secondary schools in Eleme Local Government Area of Rivers State, Nigeria, comprising 413 in the experimental group and 404 in the control group. A self structured and validated 20-item questionnaire with a reliability index of 0.78 was used for data collection. Mean and standard deviation were used to answer the research questions while Analysis of Co-variance (ANCOVA) was used to test the null hypotheses at 0.05 alpha level. Results revealed that the health education intervention increased their knowledge about alcohol with a mean gain of 0.3718. Again there was significant difference in the effects of the health education intervention on the knowledge about alcohol based on sex and religion. Based on the findings, it was concluded that a comprehensive, skill-based health education can boost the knowledge base of adolescents in Eleme LGA about alcohol. It was recommended among others that schools should invite health professionals on a regular basis to properly educate the students on the health implications of alcohol use