HRO = Human Resources Outsourcing, aka HR Management Outsourcing also known as HR Outsourcing.

HRO is where an organization hires an outside HR Manager or Consultant to oversee HR management functions related to the employment life cycle: Recruiting, Selection, Hiring, On-Boarding, Retention, Development, Transition and Separation from the company.

HR Outsourcing can also refer to the collective outsourcing of all HR related functions like Recruiting, Administration, Payroll, Employee Relations etc…