Immune thrombocytopenia (ITP) has historically been thought to occur in 2 distinct forms: childhood ITP and adult ITP. This division is based largely on the presumption that childhood ITP is often benign and self-limited, whereas ITP in adults tends to be more chronic and difficult to treat. Although data exist to justify a different approach to the diagnosis and treatment in young children and the elderly, ITP in older children, adolescents, and younger adults is likely to share more similar pathology. This article will highlight the most recent data describing the natural history, diagnostic approach, management strategies, and disease-related outcomes in children and adults with ITP. These data reveal many unexpected similarities between the 2 groups, while confirming some of the more well-described differences. Discussion of these findings aims to highlight similarities and differences between ITP in children and adults, which will underscore important areas of future research and/or changes in management guidelines.