Research into student bullying in Higher Education (HE) has been limited and most is based on childhood bullying research. Bullying in HE could disrupt student mental health and wellbeing at university - a topic that has recently gained traction. Additionally, marginalised student groups may be more at risk (e.g. LGB+). Focus groups were used to explore students’ conceptualisations of bullying and identify differences between childhood and emerging adulthood (EA) bullying behaviour. Themes identified were power imbalances; tactics of HE bullying; bullying for personal or social gain, and; justifications and minimisations for not intervening (bystander intervention). Examples of bullying behaviour from this first study supplemented the childhood and adult bullying literature to create a new HE bullying scale. The scale was tested on two samples to identify the factor structure (N = 243, N =304). The third survey study (N = 441) adopted a correlational design using the developed scale alongside measures of wellbeing, childhood victimisation, and potential mediator variables, such as university belongingness, social connectedness, and Internal Working Models (IWMs). Group differences were found on victimisation, IWMs, social connectedness, and university belonging, especially for SES and sexual orientation, evidencing the disadvantages that minority groups may suffer within HE. Regression-based path-analyses found that IWMs, university bullying, social connectedness, and university belonging mediated the links between childhood victimisation and current wellbeing. Finally, UK university anti-bullying policies were examined. Policy length and quality varied between universities and a review of content is recommended based on the earlier study findings. This research has produced a new university bullying scale and has also explored mechanisms through which childhood victimisation may have negative effects on current HE student wellbeing. The importance of self- and other- beliefs as well as the social context (e.g. belonging) is stressed.