HRO, or Human Resources Outsourcing, is the practice of outsourcing HR functions and tasks to a third-party vendor or service provider. HRO can encompass a wide range of HR services, including payroll, benefits administration, employee onboarding and offboarding, performance management, and training and development.

HRO can be a cost-effective solution for organizations that do not have the resources or expertise to manage certain HR functions in-house. By outsourcing these functions to a third party, organizations can benefit from the vendor's specialized knowledge and expertise, as well as from economies of scale.

HRO can be provided on a full-service basis, where the vendor manages all HR functions for the organization, or on a partial or à la carte basis, where the organization outsources specific HR tasks or functions as needed.

HRO can be a good fit for organizations of all sizes, but it is particularly useful for small and medium-sized businesses that may not have the resources or expertise to manage HR functions in-house. It can also be a good option for organizations that are looking to reduce costs or improve efficiency in their HR operations.