The present study investigated the prevalence of upwards bullying - that is, subordinate-initiated bullying of their supervisor - in two sample groups. Subordinates (n = 491) in this study were either thesis students working under the supervision of an academic advisor or were employees working under a primary supervisor in a variety of occupations. Participants completed a measure of bullying behaviours, the Negative Acts Questionnaire, as part of an online survey. Although the overall prevalence of bullies was low (1.7%), there was a high incidence of bullying behaviour with 70.6% of the sample reporting having engaged in bullying behaviours toward their supervisor in the preceding 6 month period. The incidence of bullying behaviours was lower for the students than for the employees and lower for females than for males. Implications for workplaces are considered. Keywords: bullying, subordinate, supervisor