Bullying is a pervasive problem in many schools and affect an increasing number of students. Its adverse psychological consequences call for implementation of early interventions, especially psychological counselling, so as to provide for appropriate individual behavioural change. This study sought to assess bullying and its psychological effects on students in public secondary schools in Nakuru Municipality. The study adopted a descriptive survey-research design targeting a population of 7904 students from 18 secondary schools. A sample of 367 students and 10 deputy head teachers was drawn from ten schools through administration of two sets of questionnaires (one for students and the other for deputy head teachers). The collected data was analyzed using descriptive and inferential statistics with the aid of The study findings indicate that there were direct and indirect forms of bullying in secondary schools with female students engaging more in indirect bullying while male students in direct bullying. Bullying had short term and long term psychological & physical effects which affected academic performance and made it difficult for students to concentrate on school work.