Some infants experience atypical levels of over-responsivity to sensations, which limit their ability to interact and explore their environment. Yet, little is known about typical development of over-responsivity during infancy or whether the presence of extreme over-responsivity in infancy is a predictor of clinically significant sensory over-responsivity (SOR) at school-age. This study followed a representative sample of children (n = 521, 47% boys) at four time points from infancy (mean ages in months Year 1 = 18.23, Year 2 = 30.39, Year 3 = 39.40) to elementary school-age (mean age = 7.97 years). SOR was measured via parent report. A latent growth curve model predicting SOR at school age from the intercept and slope of Sensory Sensitivity between Years 1-3 showed excellent fit with the data. Both early sensory sensitivities and change in early sensitivities were associated with SOR status at school-age.