In the current study, we examined latent growth in 731 young children's inhibitory control from the ages of two to four years, and whether demographic characteristics or parenting behaviors were related to initial levels and growth in inhibitory control. As part of an ongoing longitudinal evaluation of the family check-up, children's inhibitory control was assessed yearly at the ages of two to four years. Inhibitory control was initially low and increased linearly to the age of four years. High levels of harsh parenting and male gender were associated with low initial status in inhibitory control. High levels of parental positive behavior support were associated with faster growth. Extreme family poverty and African-American ethnicity were also associated with slower growth. The results highlight parenting as a target for early interventions in contexts of high socioeconomic risk.