The Common Mud Dauber Wasp (Chalybion japonicum) is an insect in the Sphecidae family of blue mud dauber wasps. It is also known as the Japanese Mud Dauber Wasp, Japanese Mud Wasp, and Japanese Dirt Dauber.

The Common Mud Dauber Wasp has a long, blue-black body with a very thin, long, waist, and a large head and abdomen. It is known as a thread-waisted body. Its wings are translucent. Its six legs dangle downward when it flies. Its eyes are large. Its antennae have 12-13 segments. It has a stinger, but stings to humans are rare.