Social norms related to fertility may be driving pregnancy desire, timing and contraceptive use, but measurement has lagged. We validated a 10-item injunctive Fertility Norms Scale (FNS) and examined its associations with family planning outcomes among 1021 women and 1020 men in India. FNS captured expectations around pronatalism, childbearing early in marriage and community pressure. We assessed reliability and construct validity through Cronbach's alpha and exploratory factor analysis (EFA) respectively, examining associations with childbearing intention and contraceptive use. FNS demonstrated good reliability (α = 0.65–0.71) and differing sub-constructs by gender. High fertility norm among women was associated with greater likelihood of pregnancy intention [RRR = 2.35 (95% CI: 1.25,4.39); ARRR = 1.53 (95% CI: 0.70,3.30)], lower likelihood of delaying pregnancy [RRR = 0.69 (95% CI: 0.50,0.96); ARRR = 0.72 (95% CI: 0.51,1.02)] and greater ambivalence on delaying pregnancy [RRR = 1.92 (95% CI: 1.18,3.14); ARRR = 1.99 (95% CI: 1.21,3.28)]. Women's higher FNS scores were also associated with higher sterilization [RRR = 2.17 (95% CI: 1.28,3.66); ARRR = 2.24 (95% CI: 1.32,3.83)], but the reverse was noted for men [RRR = 0.61 (95% CI: 0.36,1.04); ARRR = 0.54 (95% CI: 0.32,0.94)]. FNS indicated better predictive value among women compared to men for key reproductive outcomes. This measure may be useful for social norms-focused evaluations in family planning and warrants cross-contextual study.