BackgroundAddressing attitudes is central to achieving sexual and reproductive health and rights (SRHR) and Agenda 2030. We aimed to develop a comprehensive index to measure attitudinal support for SRHR, expanding opportunities for global trend analyses and tailored interventions.MethodsWe designed a new module capturing attitudes towards different dimensions of SRHR, collected via the nationally representative World Values Survey in Ethiopia, Kenya, and Zimbabwe during 2020–2021 (n = 3,711). We used exploratory factor analysis of 58 items to identify sub-scales and an overall index. Adjusted regression models were used to evaluate the index according to sociodemographic characteristics, stratified by country and sex.ResultsA 23-item, five-factor solution was identified and used to construct sub-indices reflecting support for: (1) sexual and reproductive rights, (2) neighborhood sexual safety, (3) gender-equitable relationships, (4) equitable masculinity norms, and (5) SRHR interventions. These five sub-indices performed well across countries and socioeconomic subgroups and were combined into a comprehensive “SRHR Support Index”, standardized on a 1–100 scale (mean = 39.19, SD = 15.27, Cronbach’s alpha = 0.80) with higher values indicating more support for SRHR. Mean values were highest in Kenya (45.48, SD = 16.78) followed by Ethiopia (40.2, SD = 13.63), and lowest in Zimbabwe (32.65, SD = 13.77), with no differences by sex. Higher education and being single were associated with more support, except in Ethiopia. Younger age and urban residence correlated with more support among males only.ConclusionThe SRHR Support Index has the potential to broaden SRHR attitude research from a comprehensive perspective – addressing the need for a common measure to track progress over time.