We present measurements of dust reddening using the colors of stars with spectra in the Sloan Digital Sky Survey (SDSS). We measure reddening as the difference between the measured and predicted colors of a star, derived from stellar parameters from the SEGUE Stellar Parameter Pipeline (SSPP). Our results show uncertainties of 56, 34, 25, and 29 mmag in the colors u-g, g-r, r-i, and i-z, per star. These results confirm earlier "blue tip" reddening measurements, finding reddening coefficients different by -3%, 1%, 1%, and 2% in u-g, g-r, r-i, and i-z from those found by the blue tip method, after removing a 4% normalization difference. These results prefer an R_V = 3.1 Fitzpatrick (1999) reddening law over O'Donnell (1994) or Cardelli et al. (1989) reddening laws. We provide a table of conversion coefficients from the Schlegel et al. (1998) maps of E(B-V) to extinction in 88 bandpasses for 4 values of R_V, using this reddening law and the 14% recalibration of SFD first reported by S10 and confirmed in this work. Dust is composed of heavy elements produced by the nuclear burning of stars. These heavy elements are blown out of the stars in winds and explosions, and are reprocessed in the interstellar medium to eventually form dust grains. The dust scatters and absorbs light, especially in the ultraviolet through infrared, according to the dust reddening law. The dust also emits photons thermally in the far-infrared. Mapping the dust is a central problem in astronomy. In previous work with the blue tip of the stellar locus, we examined the reddening law and the accuracy of the Schlegel et al. (1998) dust map using photometry from the SDSS and the uniformity of the color of the blue tip of the stellar locus over the sky. This blue tip work recommended a 14% recalibration of the SFD dust map in the sense that E(B-V) = 0.86 * E(B-V)_{SFD}, and a preference for a Fitzpatrick (1999) reddening law over other reddening laws. In this work we set out to test that result using an independent set of data. The SDSS stellar spectra provide an independent test of reddening. Stellar spectra sensitively test reddening because the broadband photometry of a star is almost completely determined by three parameters: temperature, metallicity, and gravity. These parameters can be determined using only line information in the spectra, allowing the intrinsic broadband colors of the star to be predicted independently from the observed colors of the star. Dust intervening between us andWe present measurements of dust reddening using the colors of stars with spectra in the Sloan Digital Sky Survey (SDSS). We measure reddening as the difference between the measured and predicted colors of a star, derived from stellar parameters from the SEGUE Stellar Parameter Pipeline (SSPP). Our results show uncertainties of 56, 34, 25, and 29 mmag in the colors u-g, g-r, r-i, and i-z, per star. These results confirm earlier "blue tip" reddening measurements, finding reddening coefficients different by -3%, 1%, 1%, and 2% in u-g, g-r, r-i, and i-z from those found by the blue tip method, after removing a 4% normalization difference. These results prefer an R_V = 3.1 Fitzpatrick (1999) reddening law over O'Donnell (1994) or Cardelli et al. (1989) reddening laws. We provide a table of conversion coefficients from the Schlegel et al. (1998) maps of E(B-V) to extinction in 88 bandpasses for 4 values of R_V, using this reddening law and the 14% recalibration of SFD first reported by S10 and confirmed in this work. Dust is composed of heavy elements produced by the nuclear burning of stars. These heavy elements are blown out of the stars in winds and explosions, and are reprocessed in the interstellar medium to eventually form dust grains. The dust scatters and absorbs light, especially in the ultraviolet through infrared, according to the dust reddening law. The dust also emits photons thermally in the far-infrared. Mapping the dust is a central problem in astronomy. In previous work with the blue tip of the stellar locus, we examined the reddening law and the accuracy of the Schlegel et al. (1998) dust map using photometry from the SDSS and the uniformity of the color of the blue tip of the stellar locus over the sky. This blue tip work recommended a 14% recalibration of the SFD dust map in the sense that E(B-V) = 0.86 * E(B-V)_{SFD}, and a preference for a Fitzpatrick (1999) reddening law over other reddening laws. In this work we set out to test that result using an independent set of data. The SDSS stellar spectra provide an independent test of reddening. Stellar spectra sensitively test reddening because the broadband photometry of a star is almost completely determined by three parameters: temperature, metallicity, and gravity. These parameters can be determined using only line information in the spectra, allowing the intrinsic broadband colors of the star to be predicted independently from the observed colors of the star. Dust intervening between us and