Health-related behaviors [physical activity (PA), nutritional quality of breakfast and sleep]; personal variables (self-esteem, attitudes to PA and gender) and socioeconomic status (SES) (school SES and parental education), were examined in relation to literacy and numeracy scores of 824 grade 3-7 children. Participants completed a questionnaire, and their national literacy and numeracy test scores were retrieved. Mothers (N = 755) completed a telephone interview. Students of highest school SES, maternal education, nutritional quality of breakfast, more sedentary time and female gender had higher literacy scores. SES, maternal education, male gender and total minutes of daily PA were predictors of numeracy with an interaction between greater total PA in boys and greater numeracy. Even though the socioeconomic factors that have predicted children's academic achievement for many decades are still clearly set in place, there are also other modifiable health influences that affect literacy and numeracy and are independent of SES. The current findings provide evidence for health educators and school administrators who may garner support for both breakfast programs and daily school PA for the dual purposes of health promotion as well as for the improvement of literacy and numeracy in settings in which social class may be acting against the educational interests of disadvantaged children.