In an example of a three-dimensional (3D) printing method, a polymeric build material is applied. A fusing agent is selectively applied on at least a portion of the polymeric build material. A mechanical tailoring agent is selectively applied on at least a region of the portion. The polymeric build material is exposed to radiation, thereby fusing the at least the portion of the polymeric build material in contact with the fusing agent to form a layer. The mechanical tailoring agent forms a composite layer in the at least the region, and the composite layer has a different mechanical property than that of an area of the layer not in contact with the mechanical tailoring agent.