Objective Improving the quality of life (QoL) of older people is a key priority for governments, clinicians, researchers and service providers worldwide. However, the lack of culturally appropriate QoL tools for First Nations people is a major barrier to such efforts. The purpose of this study was to evaluate the psychometric properties of the Good Spirit, Good Life (GSGL) QoL tool for older Aboriginal Australians. Methods One hundred and twenty older Aboriginal people living in Perth and Melbourne, Australia, were administered the GSGL tool, along with several other instruments assessing cognition (KICA-Cog), depression (KICA-Dep), anxiety (GAI-SF), health and well-being (EQ-5D-5L and ICECAP-O) and resilience (ARRQ-25). Associations between these instruments and the GSGL tool were explored to determine concurrent and known-groups validity. Internal consistency was assessed with split-half reliability and Cronbach's alpha. Exploratory factor analysis was performed to investigate construct validity. Results GSGL scores were positively correlated with ICECAP-O and ARRQ-25 scores, and negatively correlated with EQ-5D-5L score. GSGL scores differed significantly between participants with a probable anxiety disorder or depression, but not those with cognitive impairment. The Spearman-Brown prophecy estimate was 0.83 and Cronbach's alpha was 0.75. Principal component analysis identified two factors, which were labelled foundation and external. Conclusions The GSGL tool is a valid tool to assess quality of life in older Aboriginal Australians. The tool demonstrates acceptable convergent, concurrent and known-groups validity. It was co-designed at all stages with older Aboriginal people contributing to its strong face and content validity.