The Infrared Spectrograph (IRS) on Spitzer has observed more than 120 asteroids, several Centaurs and Kuiper Belt objects (KBOs), and satellites of the giant planets. The asteroid sample includes objects from near-Earth space, through the Main Belt, and into the Jupiter Trojan swarms. Asteroids from all taxonomic classes have been observed, as have several binary and multiple component systems. The diameters of these targets range from a few hundred meters to a few hundred kilometers. On the whole, IRS has provided a broad sample of emissivity spectra of small Solar System bodies. The largest emissivity features detected are at the 10% level and are confined to the more primitive asteroid classes. Significant spectral variation is apparent among the IRS asteroid sample. Some of the dust observed in the close environment of other stars likely comes from asteroid collisions, so asteroids in the Solar System are proper mineralogical analogs. As capabilities continue to improve, direct observations of small body populations in other systems and inter-comparisons between systems will foster significant insights into the formation and evolution of planetary systems. The Solar System occupies a unique role by its accessibility and the detail to which it can be studied. While the IRS data are a good start, there is much to be learned from a larger set of mid-infrared spectra (e.g., from JWST and SOFIA). In this talk, I will present an overview of the IRS observations of small Solar System bodies, with a few representative objects highlighted for detailed discussion.