Systems and methods for bidirectional gravel packing of wells. A gravel packing method includes flowing a gravel slurry in one direction in an annulus formed between a wellbore and a gravel packing assembly, and flowing another gravel slurry in an opposite direction in the annulus. A well system includes a gravel packing assembly positioned in a wellbore; one or more well screens interconnected in the gravel packing assembly; a flow control device, interconnected in the gravel packing assembly, and which selectively permits and prevents flow of a gravel slurry outward from the gravel packing assembly to an exterior of the well screens; another flow control device, interconnected in the gravel packing assembly, and which selectively permits and prevents flow of another gravel slurry outward from the gravel packing assembly to the exterior of the well screens; and the well screens being positioned between the flow control devices.