Research has indicated that a dimensional conceptualisation of psychopathology may be more accurate than the current categorical approach. Two symptom dimensions, Internalising and Externalising, have emerged, and have been linked to major trait domains of personality (the Big Five). However, previous studies have tended to focus on broader personality domains, neglecting to examine associations between sub-domains (facets). The current study addressed this gap by examining associations between facets of the Big Five and Internalising and Externalising. A sample of 290 adults (Mage=37.0, SD=14.0" 74% female) responded to a survey which included the IPIP-NEO and ASEBA Adult Self Report. Hierarchical multiple regressions identifed personality facets that may represent vulnerability factors for Internalising and Externalising. For Internalising, multiple facet-level associations were found within Neuroticism, Extraversion, and Conscientiousness, and in the latter two cases both positive and negative associations were identifed. For Externalising, most facet-level associations were found within Neuroticism and Extraversion (and to a lesser extent, Conscientiousness and Agreeableness), and were in the expected direction. In both cases, the inclusion of facets provided novel and useful information about the relationship between personality and psychopathology, which may be used to improve current methods for assessing and treating mental dysfunction.