The present longitudinal study tested the roles of early childhood executive control (EC) as well as exposure to poverty-related adversity at family and school levels as key predictors of low-income children's EC in elementary school ("n" = 391). Findings suggest that children's EC difficulties in preschool and lower family income from early to middle childhood are robust predictors of later EC difficulties as rated by teachers in 2nd and 3rd grades. Findings also suggest enrollment in unsafe elementary schools is significantly predictive of higher levels of teacher-rated EC difficulty, but only for those children who showed initially elevated levels of EC difficulty in early childhood. Implications for scientific models of cognitive development and poverty-related adversity are discussed. (Contains 1 figure, 2 footnotes, and 3 tables.)