This data set contains low-resolution (R~150) near-infrared (0.7-2.5 microns) spectra of 90 main belt asteroids observed with the SpeX instrument on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i. This data set archives reduced, calibrated spectra of targets of opportunity observed from 2001 to 2012.