Breach of fiduciary duty is a cause of action or claim in civil litigation (lawsuits) that provides the legal basis for a person or entity to recover its damages/losses when there is a special relationship based on trust and confidence (attorney and client or trustee and beneficiaries) and the party who owes the fiduciary duty breaches its duty of loyalty (conflict of interest) or duty of care (informed judgment in decision-making).

In Maryland, a breach of fiduciary duty occurs when an individual or entity, who is obligated to act in the best interest of another party due to a special trust relationship, fails to do so. This breach can involve a conflict of interest or a failure to make informed decisions in the interest of the party to whom the duty is owed. Common relationships involving fiduciary duties include those between attorneys and clients, trustees and beneficiaries, corporate directors and shareholders, and guardians and wards. When a fiduciary breaches their duty, the affected party may file a civil lawsuit to recover damages resulting from the breach. Maryland courts will evaluate whether the fiduciary acted in good faith, with the care an ordinarily prudent person in a like position would exercise under similar circumstances, and in a manner the fiduciary reasonably believes to be in the best interests of the party to whom the duty is owed. If a breach is found, remedies may include compensatory damages, profit disgorgement, and in some cases, punitive damages.