Methods, systems, and computer readable media for source peer capacity-based Diameter load sharing are disclosed. According to one aspect, the subject matter described herein includes a method for source peer capacity-based Diameter load sharing. A network element for processing Diameter messages received from a Diameter peer requests information regarding a Diameter message capacity requirement of the Diameter peer, receives information regarding the Diameter message capacity requirement of the Diameter peer, and uses the received information to load share the processing. In one embodiment, the network element is a Diameter signaling router having multiple message processors for processing Diameter messages, and the information regarding the Diameter message capacity requirement of the Diameter peer is used to load share Diameter message processing and/or Diameter connections among the multiple message processors.