Recent research has indicated that science-based achievement gaps open early in children's educational careers and are explained largely by malleable factors. Two potentially important variables to consider include children's executive function (EF) and learning-related behaviors exhibited in the classroom. These variables have been identified as key factors promoting reading and mathematics achievement, but have not been extensively examined for science outcomes. In addition to exerting individual effects on science achievement, these factors may work in tandem such that the effects of EF on science achievement are partially mediated by learning-related behaviors. To explore the effects of these variables on science achievement, the current study used a large, nationally representative sample from the Early Childhood Longitudinal Study--Kindergarten Cohort of 2010-2011. Conditional longitudinal growth curve modeling and mediation models indicated that 2 components of EF, cognitive flexibility and working memory, along with learning-related behaviors both had substantial effects on science achievement growth across children's elementary school years. The magnitude of these effects, however, was notably different for science achievement when compared with reading and mathematics achievement. Furthermore, some of the effect of cognitive flexibility and working memory on science achievement were mediated through learning-related behaviors. Results provided detailed information about the relationship between EF, learning-related behaviors, and children's growth in science achievement.