A Professional employer organization (PEO) is a firm that provides comprehensive HR solutions for businesses, including payroll administration, tax compliance, employee benefits, and risk management. PEO payroll software is a specialized solution offered by PEOs to manage and process payroll for their client businesses. By partnering with a PEO, businesses essentially co-employ their workforce with the PEO. This allows businesses to outsource many administrative tasks and responsibilities related to payroll and HR while benefiting from the PEO's expertise and infrastructure.