Techniques for flow rate based load balancing are described. In one embodiment, a method includes receiving a packet associated with a packet flow at an ingress top-of-rack switch in a spine-leaf network. The method includes determining identification information for the packet flow, including a source and a destination. Based on the identification information, the method includes determining an instantaneous flow rate for a first path through the network from the source to the destination. The method also includes comparing the instantaneous flow rate to an average flow rate. Based on the comparison between the instantaneous flow rate to the average flow rate, the method includes assigning the packet flow to one of the first path or a second path.