Early academic skills and behavioral characteristics in students are predictive of later school achievement, but academics and behavior are commonly compartmentalized in research and practice. This study investigated to what extent first-grade early numeracy (EN), literacy, and behavior ratings predicted fourth-grade mathematics achievement. In fall of first-grade, 501 students were given EN and literacy measures and a behavior rating scale completed by their teachers. In spring of fourth-grade, students were given mathematics computation and concepts assessments. Regression analyses indicated EN, early literacy, and behavior uniquely predicted 39% of the variance in participants' fourth-grade mathematics achievement. Significant predictors were EN and behavior ratings (p < 0.001), which accounted for 29% and 9% of the variance in mathematics scores, respectively.