Legal malpractice is generally the term for an attorney’s negligence when the attorney’s work or representation of the client is below the standard or duty of care for what a reasonable, prudent attorney would have done in the same or similar circumstances. Attorneys also owe their clients fiduciary duties, including the duty of loyalty. Legal malpractice and breach of fiduciary duty claims against attorneys are based on state law and vary from state to state.

In Massachusetts, legal malpractice occurs when an attorney fails to provide services at the level of care, skill, and diligence that a reasonable, prudent attorney would provide under similar circumstances, resulting in harm to the client. This standard is based on state common law, which evolves through judicial decisions. To prove legal malpractice, a client must typically show that the attorney owed a duty to the client, the attorney breached that duty, and the breach caused the client harm, usually in the form of financial loss. Additionally, attorneys in Massachusetts owe fiduciary duties to their clients, which include the duty of loyalty and the duty to act in the best interests of the client. Breach of these fiduciary duties can also give rise to a claim against an attorney. The specifics of what constitutes a breach of duty or fiduciary duty can vary, and Massachusetts courts interpret these on a case-by-case basis. It's important to note that legal malpractice claims are subject to a statute of limitations, which in Massachusetts is generally three years from the date the cause of action accrues.