Privilege may be waived by an express waiver, or an implied waiver when privileged information is disclosed to third parties. The circumstances of the dissemination determine whether there is a waiver. In 2008, the Singapore High Court approved of the following proposition for determining when a document loses privilege:

Where a document is disclosed to one or more third parties with no express or implied requirement that the third party should treat the document as confidential, there will not be any legal bar on the third party disclosing the document. However, the privilege in a document is not waived where information is imparted in the course of a relationship or venture that a reasonable person would regard as involving a duty of confidentiality and where a reasonable person in the recipient's position would regard the information as confidential.

Further, the Singapore Court of Appeal has clarified that given the importance of legal professional privilege, waiver is not to be easily implied. A court tasked to determine whether there has been an implied waiver of privilege by reason of a reference made to privileged material should approach the matter by examining all the circumstances of the case. In this regard, the Court of Appeal identified the following non-exhaustive list of factors which were relevant, namely:

• What has been disclosed (the materiality of the information in the context of the pending proceedings)
• The circumstances under which the disclosure took place (in particular, the position in the authorities appears to be that disclosures of privileged material during trial almost invariably results in a waiver)
• Whether the party had "relied" or "deployed" the advice to advance their case
• Whether there is a risk that an incomplete and misleading impression had been given

Ultimately, the court should consider whether, in all the circumstances of the case, fairness and consistency required disclosure. This is an objective inquiry, as it is the objective role played by the legal advice which is relevant and not the subjective intention of the party who is asserting privilege.

Where disclosure of privileged documents was made inadvertently to opposing parties, and unless it is too late to restore the status quo, courts will generally not allow parties to take advantage of the mistakes of their opponent; the courts may order the parties receiving the privileged documents to return the documents, and those parties will be restrained from using the information contained in those documents.

Although the courts of Singapore have not considered the precise point of whether the doctrine of limited waiver applies in Singapore, it is possible to argue that the doctrine will apply based on the above dictum.

The courts of Singapore have recognized that common interest privilege (i.e., a privilege in aid of anticipated litigation in which several persons have a shared interest) applies in Singapore. This allows sharing of privileged materials with others who have a common interest in the subject matter to which the privileged materials relate without any loss of legal privilege.

Inadvertent disclosure of part of a memorandum may also result in a waiver of privilege in respect of the other parts of the memorandum where there can be no informed argument without the disclosure.