Layer-7 application layer message (“message”) classification is disclosed. A network traffic management device (“NTMD”) receives incoming messages over a first TCP/IP connection from a first network for transmission to a second network. Before transmitting the incoming messages onto the second network, however, the NTMD classifies the incoming messages according to some criteria, such as by assigning one or more priorities to the messages. The NTMD transmits the classified messages in the order of their message classification. Where the classification is priority based, first priority messages are transmitted over second priority messages, and so forth, for example.