A direct-view handheld binocular spectrometer for use in a variety of educational settings. The device comprises a holographic transmission diffraction grating and a uniquely curved quantitative wavelength scale for viewing visible-wavelength spectra with both eyes simultaneously. A variable width entrance slit, adjustable illumination for the wavelength scale, and attachable corrective lenses enhance the ease of use and efficiency as compared to traditional monocular spectrometers.