An example of a three-dimensional (3D) printing kit includes a build material composition and a fusing agent to be applied to at least a portion of the build material composition during 3D printing. The build material composition includes a thermoplastic elastomer having: an avalanche angle ranging from about 49 degrees to about 59 degrees; a break energy ranging from about 55 kJ/kg to about 78 kJ/kg; and an avalanche energy ranging from about 10 kJ/kg to about 27 kJ/kg. The fusing agent includes an energy absorber to absorb electromagnetic radiation to coalesce the thermoplastic elastomer in the at least the portion.