A concerning number of students fail to achieve writing proficiency, yet little attention has been devoted to examining why this occurs. While robust evidence indicates that behavior impacts reading and math achievement, the relationship between behavior and writing skills is unclear, particularly among young students. The authors examined the value of behavior screeners in predicting writing achievement, beyond the variance explained by early writing screeners alone. Additionally, various behavior domains (e.g., emotional, social, hyperactivity/inattention) were compared for their relative utility in predicting writing achievement. Data from a study of 95 kindergarteners were used for the analysis. Hierarchical regression was used to evaluate the added explained variance of the behavior screener and to compare the predictive ability of its domains. Results suggest that while problem behaviors and writing skills are negatively correlated, behavior screening does not improve on the ability of early writing screeners to predict concurrent writing achievement. The refinement of tools that predict writing achievement may improve the early identification of academic difficulties and allow educators to intervene before academic problems become intractable.