S100A13, also known as S100 calcium binding protein A13, is a member of the S100 family of proteins containing 2 EF-hand calcium-binding motifs. S100 proteins are localized in the cytoplasm and/or nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. It plays a role in the export of proteins that lack a signal peptide and are secreted by an alternative pathway. S100A13 protein has been shown to interact with SYT1 and FGF1.