The general rule is that disclosing a privileged document to a third party waives the privilege, because confidentiality is its cornerstone (Bank of Lisbon and South Africa Ltd v. Tandrien Beleggings (Pty) Ltd and Others). The test for waiver is objective and depends on whether the conduct is inconsistent with maintaining confidentiality. Inadvertent disclosure may not constitute a waiver if reasonable steps were taken to maintain confidentiality, but the decision in Ibex RSA Holdco Ltd v. Tiso Blackstar Group (Pty) Ltd established that deliberately publishing summaries of privileged documents waives privilege over the entire document.

However, a document can be shared with a third party without losing protection in specific circumstances. Litigation privilege is designed to cover communications with third parties, such as expert witnesses, where the dominant purpose is for use in pending or contemplated litigation (General Accident, Fire and Life Assurance Corporation Ltd v. Goldberg). Common interest privilege preserves the protection when a document is shared with a third party that has a sufficient common legal interest in the matter, such as codefendants or companies in the same group (Anglo American South Africa Limited v. Kabwe and 12 Others). A document may also be disclosed for a limited and specific purpose under strict terms of confidentiality (e.g., to an auditor) without a general waiver, though, if confidentiality is ultimately breached, privilege cannot be used to suppress publication (South African Airways Soc v. BDFM Publishers (Pty) Ltd and Others).

Finally, disclosure to a necessary agent of the lawyer or client, such as an interpreter, will generally not waive privilege.