Addressing physical literacy (PL) has become increasingly relevant to counteract sedentary behaviour in children and youth. We developed an assessment tool to measure and evaluate the promotion of individual PL and its four subdomains: motivation and confidence (the affective dimension), physical competence (physical dimension), knowledge and understanding (cognitive dimension), and participation in physical activity. Within this cross-sectional study, we tested 567 children aged 6–12 years from four primary schools that differed in socioeconomic status (SES). A subsequent exploratory factor analysis conducted to examine the conformity revealed a five-factor structure. The five factors explained 39.8% of the total cumulative variance. Children with a low SES yielded lower scores in all subdomains except participation in physical activity. This effect was most pronounced in motor skills (p < 0.001, r = 0.28). Among the children with a low SES, 16.9% were overweight and 17.4% were obese, compared to 11.5% and 5.4%, respectively, for those with a high SES (p < 0.001). In conclusion, although the assessment tool was largely in line with the postulated structure, further adjustments are necessary in terms of participation and motivation. Nevertheless, this holistic view of PL, taking SES into account, should enable the focused promotion of health and health literacy.