Stink bugs come in a wide palette of colors, from lime green to inky black. Some have intense markings on their bodies, but most take on a fairly solid color. While many of the stinkbugs you'll encounter will likely take on a brownish appearance, the University of Florida notes that the green stink bug is the most commonly encountered species in the United States. It's a solid light green in color.
Stinkbugs range slightly in size, generally coming in between 1/3 inch and and 3/4 inch in length, give or take a smidgen. The bugs are also known as shield bugs, and for good reason. The outer shell that covers them typically takes on a shieldlike appearance, either triangular or somewhat rounded in shape. On the back of that shell is a smaller shield, also triangular or somewhat rounded in shape. This is known as the scutella and it's essentially a hard piece of armor that protects a stink bug. Animal Planet notes that some stink bugs have scutellas so large they cover nearly their entire backs.
Stink bugs have two antennae with five segments each. They use their antennae to help feel around in their environment. Most stink bugs have colored bands around their antennae. The insects sport three pairs of legs and two pairs of overlapping wings. The front wings are known as hemelytra -- the base of each wing is hardened; the tips, along with the entirety of the back wings, are thin and somewhat transparent.