Early childhood development research typically focusses on populations that are either of upper or lower socioeconomic status. A population especially overlooked is the 'missing-middle', represented by middle-income, urban populations. Knowledge of children's development from middle-income populations to guide the implementation and customisation of early intervention policies, is needed. The Vineland-3 was used to describe the developmental outcomes of 55 young children, six to 24 months old, from an urban, middle-income setting in South Africa. The mHealth PEDS was used to identify caregivers' developmental concerns. Caregivers' concerns were positively associated with their children's developmental outcomes ([phi] = 0.355; p = 0.024), emphasising their valuable contribution in early identification of developmental delays. Fifteen percent (n = 8) of participants' children presented with developmental delays, with low birth weight identified as a significant risk ([phi] = 0.415; p = 0.011) and higher maternal education as a significant protective factor ([phi] = 0.365; p = 0.016). High gross motor proficiency appears to be a strength within this population, while receptive language and play skills require attention. Early childhood development should be prioritised across all socioeconomic classes to help ensure that children from the 'missing-middle' do not miss out on the opportunity to thrive.