Young women's experiences with sexual and reproductive health (SRH) stigma may contribute to unintended pregnancy. Thus, stigma interventions and rigorous measures to assess their impact are needed. Based on formative work, we generated a pool of 51 items on perceived stigma around different dimensions of adolescent SRH and family planning (sex, contraception, pregnancy, childbearing, abortion). We tested items in a survey study of 1,080 women ages 15 to 24 recruited from schools, health facilities, and universities in Ghana. Confirmatory factor analysis (CFA) identified the most conceptually and statistically relevant scale, and multivariable regression established construct validity via associations between stigma and contraceptive use. CFA provided strong support for our hypothesized Adolescent SRH Stigma Scale (chi-square p value < 0.001; root mean square error of approximation [RMSEA] = 0.07; standardized root mean square residual [SRMR] = 0.06). The final 20-item scale included three subscales: internalized stigma (six items), enacted stigma (seven items), and stigmatizing lay attitudes (seven items). The scale demonstrated good internal consistency (α = 0.74) and strong subscale correlations (α = 0.82 to 0.93). Higher SRH stigma scores were inversely associated with ever having used modern contraception (adjusted odds ratio [AOR] = 0.96, confidence interval [CI] = 0.94 to 0.99, p value = 0.006). A valid, reliable instrument for assessing SRH stigma and its impact on family planning, the Adolescent SRH Stigma Scale can inform and evaluate interventions to reduce/manage stigma and foster resilience among young women in Africa and beyond.