This paper examines one type of negative work behaviour, work harassment, using two theoretical frameworks: Social Exchange Theory (SET) and Similarity-Attraction (SA). SET explains work harassment as a product of poor management practices, whereas using SA theory explains it as a result of the growing normalisation of high workloads. The study undertakes latent mean and path model comparison analysis using structural equation modelling of data from 189 nurses in the UK and 401 nurses in the USA. The findings indicate a good model fit showing a significant path from Leader Member Exchange (LMX) to work harassment, wellbeing and subsequent turnover intentions, with LMX fully mediating the path from LMX to wellbeing for UK nurses, but only partially mediating the same path for nurses in the USA. The findings suggest SET provides a better explanation for work harassment for UK nurses, whereas SA theory better explains the US nurse experience.