Recognition and interpretation of emotional facial expressions are important developmental processes that are integral to social relations. Regardless of where or when people are interacting, the neural system regulating emotional facial expressions is tested daily in a variety of settings and scenarios. In spite of this, little is known regarding the neural framework underlying emotional facial expression in children. When do typically developing children recognize and understand certain emotions? How does this understanding improve over the course of development? What is the role of the visuospatial system? What are the neural substrates and how do they develop? The goal of this study is to elaborate on the developmental course of processing emotional facial expression and its underlying neural organization. We completed a normative study on 122 typically developing children from a local elementary school, ranging in age from 4 years, 0 months to 8 years, 6 months, to map the development of perceptual categories for emotion. Eighteen children with early unilateral focal brain injury (PL) were recruited from two large New York hospitals. The study included a computerized battery of four tests, focusing on the ability to appropriately match faces and facial movements, and also to identify and interpret emotional expression. It was hypothesized that as perceptual categories for emotion develop into school-age for all children, the effects of perinatal lesion (PL) on either side of the brain would negatively impact the discrimination and recognition of emotional facial expression. It was also anticipated that children with right perinatal lesions (RPL) would be the most impaired overall, especially in the interpretation of emotions with positive valence. Finally, we reviewed all three groups' ability to match non- emotional facial movements, hypothesizing that children with RPL would perform worse than typically developing (TD) peers and children with left perinatal lesion (LPL) due to the impairment of key visuo-spatial modalities in the right hemisphere. While children in the PL group were expected to improve over time, we believed that subtle yet persistent impairments in emotion processing would remain throughout childhood. Results varied somewhat from the hypotheses in that children with LPL and RPL both showed significant impairment. Children in both PL groups showed delays in matching and identification of emotions. Both PL groups displayed impairment in matching and identifying the emotions of fear and anger; in addition, children in the LPL group faced greater difficulty than their TD peers identifying and matching surprise and happiness. Children in both PL groups also displayed deficits detecting non-emotional facial movements. Across all tests, there were no significant differences between PL groups. Additional studies including more PL subjects are needed for confirmation; however, our study provides evidence that children with PL face greater difficulty recognizing and interpreting emotions based on facial behaviors alone, reflecting constraints on neuroplasticity.