Individuals who effectively regulate or mildly increase their systolic blood pressure (SBP) in response to an orthostatic challenge exhibit healthier affective status, cognitive functioning, and better quality of life. Thus, increased SBP in response to an orthostatic challenge serves as a proxy for several underlying changes. This study examined the relationship between SBP regulation and self-esteem in children. Data were collected from 92 boys and girls, aged 8–11 years. Systolic, diastolic, and pulse measurements were obtained after 5 minutes of remaining supine and again after 1 minute of standing. Children also provided affective ratings on the Children's Depression Inventory. The Negative Self-Esteem subscale was examined for this study. A multiple regression analysis revealed that poorer orthostatic regulation was associated with higher levels of negative self-esteem among children aged 8–11 years. Thus, orthostatic BP regulation may serve as a biological marker for poor self-esteem in children. This may have further implications for children's emotional functioning as low self-esteem may serve as a risk factor for future negative affective states.