An individual responsible for managing the day-to-day affairs and the strategic decisions involved with a group's pension fund/plan. More specifically, the plan administrator ensures that money is being contributed into the fund, the proper asset allocation decisions are made and that payouts are promptly distributed among all qualified plan participants or beneficiaries.

For smaller companies, and for simplicity and cost savings purposes, the employer may elect to be the company's pension plan administrator. However, as the number of employees grows, the task will often become more time consuming and complex and it is often more worthwhile for the employer to hire a professional to be the pension plan administrator.

In terms of fiduciary duty, the pension plan administrator has a duty to act in the interest of the plan's participants and not the underlying company.