Superstring theory is an elegant theoretical framework providing a unified description of gravity, quantum mechanics, gauge forces, and matter. Until recently it was thought that the natural energy scale for superstring physics was set by the reciprocal square root of Newton's gravitational constant G. Since this energy scale is a factor of 10^16 times the reach of current particle accelerators, it was thought that superstring theory could have no direct overlap with experiments. It is now believed that the fundamental energy scale of superstring physics may be far lower, perhaps as low as 1 to 10 TeV. In this case current and future particle colliders can probe or constrain a rich variety of new physical phenomena associated with superstrings. These new phenomena include effects from new dimensions of space, quantum gravity, and the vibrational modes of the superstring.