Canadian common law recognizes the concept of privilege as a shield that protects against the mandatory disclosure of much of the communication that passes back and forth between a lawyer and their client. The privilege belongs to the client, not the lawyer, and can therefore be waived only by the client. In the province of Quebec, a civil law jurisdiction, solicitor-client privilege is referred to as "professional secrecy".

Solicitor-client (or attorney-client) privilege protects the direct communications – both oral and documentary – prepared by the lawyer or client and flowing between them in connection with the provision of legal advice. To be protected, the communication must be intended to be made in confidence, in the course of seeking or providing legal advice, and must be advice based upon the professional's expertise in law. Solicitor-client privilege is no longer considered to be a rule of evidence in Canada, but a substantive rule that has evolved into a fundamental civil and constitutional right. The privilege is not absolute, but it is as close to absolute as possible to ensure public confidence and retain relevance. It will yield only in certain clearly defined circumstances, including where an accused's innocence is at stake, where the communications at issue are criminal or have a view to facilitating the commission of a crime, where public safety requires protection, where a client puts their reliance on legal advice in issue, or where a client and lawyer are adversaries in litigation.

Litigation privilege, also called work product privilege, applies to communications between a lawyer and third parties or a client and third parties, or to communications generated by the lawyer or client for the dominant purpose of litigation when litigation is contemplated, anticipated or ongoing. Generally, it is information that counsel or persons under counsel's direction have prepared, gathered or annotated. As set out by the Supreme Court of Canada in Blank v. Canada, the purpose of the privilege, "[…] is to create a 'zone of privacy' in relation to pending or apprehended litigation" so that litigants can, "[…] prepare their contending positions in private, without adversarial interference and without fear of premature disclosure." The privilege is lost when litigation-privileged materials are tendered or relied upon in court.