OBJECTIVE: To determine whether maternal use of tenofovir disoproxil fumarate for treatment of HIV in pregnancy predicts fetal and infant growth. METHODS: The study population included HIV-uninfected live-born singleton infants of mothers enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group protocol P1025 (born 2002-2011) in the United States and exposed in utero to a combined (triple or more) antiretroviral regimen. Infant weight at birth and 6 months was compared between infants exposed and unexposed to tenofovir in utero using 2-sample t test, chi test, and multivariable linear and logistic regression models, including demographic and maternal characteristics. RESULTS: Among 2025 infants with measured birth weight, there was no difference between those exposed (N = 630, 31%) versus unexposed to tenofovir in mean birth weight (2.75 vs. 2.77 kg, P = 0.64) or mean gestational age- and sex-adjusted birth weight z-score (WASZ) (0.14 vs. 0.14, P = 0.90). Among 1496 infants followed for 6 months, there was no difference in mean weight at 6 months between tenofovir-exposed (N = 457, 31%) and tenofovir-unexposed infants (7.64 vs. 7.59 kg, P = 0.52) or in mean WASZ (0.29 vs. 0.26, P = 0.61). Tenofovir exposure during the second/third trimester, relative to no exposure, significantly predicted underweight (WASZ < 5%) at age 6 months [odds ratio (95% confidence interval): 2.06 (1.01 to 3.95), P = 0.04]. Duration of tenofovir exposure did not predict neonatal or infant growth. CONCLUSIONS: By most measures, in utero exposure to tenofovir did not significantly predict infant birth weight or growth through 6 months of age.