This study aimed to examine the psychometric properties of the PROMIS depression, anxiety, and anger item banks in a large Australian population-based sample. The study tested for unidimensionality; evaluated invariance across age, gender, and education; assessed local independence; and tested item bank scores as an indicator for clinical criteria. In addition, equivalence of the 7-day time frame against an alternative 30-day time frame was assessed. A sample of 3,175 Australian adults were recruited into the study through online advertising. All three item banks showed strong evidence of unidimensionality and parsimony, with no items showing local dependence. All items were invariant across age, gender, and education. The item banks were accurate in detecting clinical criteria for major depressive disorder, generalized anxiety disorder, and panic disorder, although legacy measures designed for this purpose sometimes performed marginally better. Responses to the 30-day time frame were highly consistent with the original 7-day time frame. The study provided support for the validity of the PROMIS emotional distress item banks as measures of depression, anxiety, and anger in the Australian population, supporting the generalizability of the measures. The time frame chosen for assessing mental health outcomes using these item banks should be based on pragmatic considerations.