Methods, systems, and devices supporting global message threads are described. A thread server may receive a communication message associated with a first set of user identifiers (e.g., the author and recipients of the message) and may extract a thread identifier from the message. The thread identifier may associate the message with one or more additional messages (e.g., from the same thread of messages), where the one or more additional messages may be associated with different user identifiers. The thread server may upsert the received communication message to a stored set of messages associated with a root indicating the thread identifier. If the thread server receives a query indicating the thread identifier from a user, the thread server may retrieve all of the messages associated with the thread identifier from persistent memory based on the query, including messages that are not associated with the user identifier for the querying user.