Background Aboriginal and Torres Strait Islander leaders call for strengths-based approaches to counter deficit narratives and promote health equity. This study developed the first Strengths Index (SI) to examine whether strengths modify the association living with frailty has with social and emotional wellbeing (SEWB) in Aboriginal and Torres Strait Islander peoples aged 45 to 80 years. Methods Guided by a Community Reference Group of Elders, we pooled data from two nationally representative cross-sectional surveys (2019 and 2023 National Aboriginal and Torres Strait Islander Health Surveys). A 56-item Frailty Index (FI) and 48-item SI were developed. The SI comprised non-frailty psychosocial factors considered to enhance SEWB (e.g., family support). Participants were classified into four groups based on frailty (High/Low) and strengths (High/Low). Generalised linear models examined associations between indices and four validated SEWB outcomes (vitality, low distress, emotional wellbeing and positive wellbeing). Results Data for 4,697 Aboriginal and Torres Strait Islander adults (mean±SD 58.4±9.0 years, 56% women), indicated that strengths and frailty increased with age, with women showing higher levels of both than men (p<.001). Those with High Frailty/High Strengths had greater SEWB than High Frailty/Low Strengths (odds ratios ranged from 2.2–3.6 across outcomes, p<.001). Discussion Our novel study presents a methodology to measure strengths and builds on calls from Community leaders to centre strengths in efforts toward health equity. Our group will continue working together with older Aboriginal and Torres Strait Islander peoples using qualitative yarning circles for co-creation of a strengths-based frailty assessment and management toolkit.