Group A Streptococcus (GAS) is a Gram-positive pathogen ranked as the ninth leading infectious cause of human mortality worldwide by the World Health Organisation (WHO). There is no vaccine available; however vaccine development to date has focused significantly on the highly abundant GAS cell surface M protein. This has paralleled the extensive characterisation of the molecular mechanisms of M protein mediated GAS pathogenesis. However, M protein derived vaccine development has been hindered due to diversity of the M protein between GAS isolates. The M protein is located in the multiple gene activator regulon of GAS adjacent to the M related protein (Mrp) and the M like protein (Enn). Mrp is a GAS surface protein encoded in the genome of approximately 80% of GAS strains. There is evidence to suggest that Mrp plays a multi-faceted role in pathogenesis, contributing to immune evasion, adherence to host cells, and biofilm formation. Mrp has also been identified as a potential vaccine candidate, and incorporation of Mrp into a multivalent vaccine may provide additional coverage in regions of high M diversity. However the molecular mechanisms underpinning the role of Mrp in GAS pathogenesis need to be further investigated, with the consideration of Mrp diversity and structure. Using surface plasmon resonance, we have characterised the ability of phylogenetically diverse Mrp proteins to bind host ligands including fibrinogen and IgG. Understanding which host proteins interact with Mrp on the GAS cell surface, and the degree of binding diversity within the Mrp family will further the understanding of Mrp function, enhancing our understanding of the molecular mechanisms underlying GAS disease.