A computer-implemented method for detecting client types may include identifying a communication from a client system transmitted according to a network protocol, analyzing the communication to determine at least one protocol implementation characteristic that describes how the client system implemented the network protocol in the communication, submitting the protocol implementation characteristic to a protocol implementation database that correlates client types with protocol implementation characteristics and receiving, in response to submitting the protocol implementation characteristic, a client type of the client system. Various other methods, systems, and computer-readable media are also disclosed.