We present a grid of stellar classification spectra of moderate resolution (R~1500) in the range lambda lambda 5600-9000A, compiled from high signal-to-noise spectra of 275 stars, most in the open clusters Praesepe and M 67. The grid covers dwarfs from types B8 through M5, giants from G8 through M7, and subgiants from F5 through K0. We catalog atomic and molecular absorption features useful for stellar classification, and demonstrate the use of luminosity-sensitive features to distinguish between late-type dwarf and giant stars.