A fiduciary duty that requires a director of a corporation to act and make decisions in the best interest of the corporation, not in the director's own personal interest. The duty of loyalty is governed by state law. See also duty of care.

Under Section 102(b)(7) of the Delaware General Corporation Law, Delaware corporations cannot eliminate or limit the personal liability of directors for breaches of the duty of loyalty, even though they can do so for breaches of the duty of care.

In cases where a party breaches the duty of loyalty, that party usually must disgorge the profits that it gained from the breach.