In recent decades, obesity prevalence in the US remains high and has begun presenting earlier in the lifespan, with 10% of all children between birth and 2 years of age being categorized as high weight-for-length. Rapid weight gain (RWG) during infancy predicts greater risk of obesity, metabolic complications, and related medical problems throughout the lifespan. Despite these implications, underlying mechanisms of the infant that contribute to eating behaviors and weight status remain poorly understood. Individual differences in reward response may emerge very early in life and could underlie risk for RWG in infancy. A promising method for studying magnitude of reward in infants is through the analysis of well-established facial responses to sweet tastes (i.e. sucrose solutions) that indicate liking/pleasure. This study measured the frequency of liking-related facial responses to the delivery of sucrose solutions compared to water in 119 babies. Compared to prior research in small samples of newborns, the magnitude and range of facial responses to sucrose was reduced in older infants. Furthermore, this study did not find evidence that amplified facial responsivity to sucrose was predictive of RWG in the first 6 months of life.