There is limited empirical evidence on how LGBTIQ (Lesbian, Gay, Bisexual, Transgender, Intersex and Queer/Questioning) people cope with stigma-related stress associated with marriage amendment processes. The current study explored coping during the 2017 Australian Marriage Law Postal Survey during which stigma-related stress was significantly associated with increased psychological distress of LGBTIQ people. Data collected during the voting and debate period from 5,453 LGBTIQ respondents were analyzed, investigating relationships between coping strategies and psychological distress. In keeping with this study's aims to provide scholarship on the poorly understood relationship between coping with stigma-related stress and mental health of LGBTIQ people, qualitative data were used to complement quantitative analysis. Emotion-focused, avoidant coping strategies of reactive distancing and disengagement was associated with increased psychological distress, as expected. However, contrary to expectations based on coping and stress theories, problem-focused, adaptive coping strategies, including LGBTIQ community engagement and activism, problem solving, positive reappraisal, and seeking social support were not associated with reduced psychological distress. Results reveal the limitations of problem-focused coping in the context of extreme stigma-related stress, with adaptive coping efforts commonly unsuccessful due to highly pervasive stressors. Findings also highlight that typical problem-focused coping strategies may not be sufficient for dealing with identity threats such as those experienced during this period. Findings support the importance of structural equality in reducing psychological distress of minorities and indicate the need for improved community and therapeutic support and addressing stigma-related stress as a social, rather than individual phenomenon.