Despite evidence showing that emotion dysregulation is a key feature of Borderline Personality Disorder (BPD), it remains unclear how the process of emotion regulation is disrupted in this population. This thesis makes an original contribution to knowledge by exploring how emotion regulation is conducted by individuals with high levels of Borderline Personality Features (BPF), in an attempt to clarify the features of emotion regulation that may be problematic for these individuals. This was achieved using a multi-methodological approach with student samples to investigate several aspects of emotion regulation that have been identified in the literature as being important for emotion regulation success in relation to BPF. Study 1 investigated the overall experiences of emotion regulation and the types of emotion regulation strategies used by individuals with high levels of BPF using semi-structured interviews. Study 2a built on findings of Study 1 by quantifying the type and number of strategies used for positive and negative emotion regulation attempts using self-report questionnaires. Study 2b investigated the intensity of emotions when regulated and the duration of emotion regulation attempts using Experience Sampling Methodology (ESM).The final study, Study 2c, investigated implicit valuing of emotion regulation and emotion utility using two computer-based implicit tasks. Findings from studies 1 and 2a demonstrated that although individuals with high-levels of BPF demonstrate knowledge of a range of strategies, they appear to select and implement more unhelpful strategies and less helpful strategies. Moreover, this was found for the regulation of negative and positive emotion regulation. This finding provides evidence for a sufficient knowledge of emotion regulation strategies in this population, an area currently disputed within the literature. Additionally these findings address important gaps in the literature regarding positive emotion regulation and the use of helpful strategies in this population, areas neglected in past research. Findings from study 2b demonstrated that individuals with high levels of BPF appear to regulate their negative emotions when emotion intensity is higher. Theoretically, this indicates that these individuals attempt to regulate their emotions later in the emotion generation process, when intensity is high. However, BPF did not predict an increase in the duration of negative emotion regulation attempts, despite past research demonstrating that longer periods of emotion regulation may be necessary when emotion intensity is high. Together these findings highlight two potentially problematic areas of emotion regulation for individuals with high levels of BPF; timing and duration of emotion regulation attempts. Past research suggests that this pattern of emotion regulation influence emotion regulation strategy choice and limits emotion regulation success. In addition, it was also found that BPF predicted shorter durations of positive emotion regulation attempts. The investigation of positive emotion regulation has been largely neglected in the field of BPF. Thus this finding makes a unique contribution to the literature by indicating that these individuals may also demonstrate disturbances in positive emotion regulation processes. Findings from the final study, Study 2c, suggest that individuals with high levels of BPF do not differ in their implicit evaluations of emotion expression or emotion control, suggesting that implicit motivation for emotion regulation is not disrupted in this population. However, it was found that these individuals implicitly perceive avoidance emotions, such as worry or nervousness, as unhelpful when faced with a threatening task. This suggests that these individuals may demonstrate deficits in their understanding of emotion utility and ability to use emotions effectively. Overall, the research included in this thesis makes an important theoretical contribution to the literature by identifying specific features within the emotion regulation process that may be problematic for individuals with high levels of BPF. The identification of these features has important implications for non-clinical support services by highlighting specific targets for treatment. These findings may also be useful in informing clinical interventions for emotion dysregulation, subject to replication in clinical populations.