Technologies for aggregation-based message processing include multiple computing nodes in communication over a network. A computing node receives a message from a remote computing node, increments an event counter in response to receiving the message, determines whether an event trigger is satisfied in response to incrementing the counter, and writes a completion event to an event queue if the event trigger is satisfied. An application of the computing node monitors the event queue for the completion event. The application may be executed by a processor core of the computing node, and the other operations may be performed by a host fabric interface of the computing node. The computing node may be a target node and count one-sided messages received from an initiator node, or the computing node may be an initiator node and count acknowledgement messages received from a target node. Other embodiments are described and claimed.