Interleukin-17A (IL-17A) and its receptor (IL-17RA) are prototype members of IL-17 ligand/receptor family firstly identified in CD4+ T cells, which comprises six ligands (IL-17A to IL- 17F) and five receptors (IL-17RA to IL-17RE). IL-17A is predominantly secreted by T helper 17 (Th17) cells, and plays important roles in the development of autoimmune and inflammatory diseases. IL-17RA is widely expressed, and forms a complex with IL-17RC. Binding of IL-17A to this receptor complex triggers the activation of several intracellular signaling pathways. In this review, we aimed to summarize literature data about molecular features of IL-17A and IL-17RA from gene to mature protein. We are also providing insight into regulatory mechanisms, protein structural conformation, including ligand-receptor interaction, and an overview of signaling pathways. Our aim was to compile the data on molecular characteristics of IL-17A and IL-17RA which may help in the understanding of their functions in health and disease.