Mental harassment as a method of managing pupil discipline in primary schools is currently unlawful in line with the Basic Education Act, 2013 after it had been established to be one of the causes of pupil indiscipline. However, despite the ban, by the year 2015, Emuhaya Sub-County had a higher rate of indiscipline cases where there were 833 (53%) cases, 644(43%) in Vihiga Sub-County and 543(37%) in Hamisi Sub county; and 2750 (42%) at national level. The objective of the study was to establish the influence of implementation of ban of mental harassment on pupil discipline in Emuhaya Sub County. A conceptual framework consisting of implementation of ban of mental harassment as the independent variable and pupil discipline as the dependent variable was used. The results showed that there was a weak negative relationship between mental harassment and level of discipline of pupils: where r = -.065, N=71 and P > .05. This meant that ban of mental harassment did not significantly influence pupil discipline. The study recommends that ban of mental harassment be fully implemented in primary schools. The study is significant in as it informs the stakeholders in education, that is learners, teachers, policy makers and members of school management boards that mental harassment ban should be reconsidered in primary schools with the view of improving pupil discipline.