Integrating measures of respectful care is an important priority in family planning programs, aligned with maternal health efforts. Ensuring women can make autonomous reproductive health decisions is an important indicator of respectful care. While scales have been developed and validated in family planning for dimensions of person-centered care, none focus specifically on decision-making autonomy. The Mothers Autonomy in Decision-Making (MADM) scale measures autonomy in decision-making during maternity care. We adapted the MADM scale to measure autonomy surrounding a woman's decision to use a contraceptive method within the context of contraceptive counselling. This study presents a psychometric validation of the Family Planning Autonomous Decision-Making (FP-ADM) scale using data from Argentina, Ghana, and India. We used cross-sectional data from women in four subnational areas in Argentina (n = 890), Ghana (n = 1,114), and India (n = 1,130). In each area, 20 primary sampling units (PSUs) were randomly selected based on probability proportional to size. Households were randomly selected in Ghana and India. In Argentina, all facilities providing reproductive and maternal health services within selected PSUs were included and women were randomly selected upon exiting the facility. Interviews were conducted with a sample of 360 women per district. In total, 890 women completed the FP-ADM in Argentina, 1,114 in Ghana and 1,130 in India. To measure autonomous decision-making within FP service delivery, we adapted the items of the MADM scale to focus on family planning. To assess the scale's psychometric properties, we first examined the eigenvalues and conducted a parallel analysis to determine the number of factors. We then conducted exploratory factor analysis to determine which items to retain. The resulting factors were then identified based on the corresponding items. Internal consistency reliability was assessed with Cronbach's alpha. We assessed both convergent and divergent construct validity by examining associations with expected outcomes related to the underlying construct. The Eigenvalues and parallel analysis suggested a two-factor solution. The two underlying dimensions of the construct were identified as "Bidirectional Exchange of Information" (Factor 1) and "Empowered Choice" (Factor 2). Cronbach's alpha was calculated for the full scale and each subscale. Results suggested good internal consistency of the scale. There was a strong, significant positive association between whether a woman expressed satisfaction with quality of care received from the healthcare provider and her FP-ADM score in all three countries and a significant negative association between a woman's FP-ADM score and her stated desire to switch contraceptive methods in the future. Our results suggest the FP-ADM is a valid instrument to assess decision-making autonomy in contraceptive counseling and service delivery in diverse low- and middle-income countries. The scale evidenced strong construct, convergent, and divergent validity and high internal consistency reliability. Use of the FP-ADM scale could contribute to improved measurement of person-centered family planning services.