Diameter-dependent Raman scattering in single tapered silicon nanowires is measured and quantitatively reproduced by modeling with finite-difference time-domain simulations. Single crystal tapered silicon nanowires were produced by homoepitaxial radial growth concurrent with vapor–liquid–solid axial growth. Multiple electromagnetic resonances along the nanowire induce broad band light absorption and scattering. Observed Raman scattering intensities for multiple polarization configurations are reproduced by a model that accounts for the internal electromagnetic mode structure of both the exciting and scattered light. Consequences for the application of Stokes to anti-Stokes intensity ratio for the estimation of lattice temperature are discussed.