Elisabete da Cunha, Stéphane Charlot, and David Elbaz present a simple, empirical, and physically motivated model to interpret the mid- and far-infrared spectral energy distributions (SEDs) of galaxies, consistent with their emission at ultraviolet, optical, and near-infrared wavelengths. The model relies on an existing angle-averaged prescription to compute the absorption of starlight by dust in stellar birth clouds and the interstellar medium (ISM). The SED of dust reradiated power is decomposed into three components: polycyclic aromatic hydrocarbons (PAHs), a mid-infrared continuum from hot grains (130–250 K), and grains in thermal equilibrium with adjustable temperatures (30–60 K). For the ambient ISM, the relative proportions of these components are fixed to reproduce the diffuse cirrus emission in the Milky Way, and a component of cold grains (15–25 K) is included. This versatile model allows for statistical constraints on star formation histories and dust contents of large galaxy samples using UV, optical, and infrared observations. The authors apply this model to 66 nearby star-forming galaxies from the Spitzer Infrared Nearby Galaxy Survey (SINGS) and find strong correlations between mid- and far-infrared colors and specific star formation rates, as well as other galaxy-wide properties. The model can be applied to interpret SEDs from any galaxy sample.Elisabete da Cunha, Stéphane Charlot, and David Elbaz present a simple, empirical, and physically motivated model to interpret the mid- and far-infrared spectral energy distributions (SEDs) of galaxies, consistent with their emission at ultraviolet, optical, and near-infrared wavelengths. The model relies on an existing angle-averaged prescription to compute the absorption of starlight by dust in stellar birth clouds and the interstellar medium (ISM). The SED of dust reradiated power is decomposed into three components: polycyclic aromatic hydrocarbons (PAHs), a mid-infrared continuum from hot grains (130–250 K), and grains in thermal equilibrium with adjustable temperatures (30–60 K). For the ambient ISM, the relative proportions of these components are fixed to reproduce the diffuse cirrus emission in the Milky Way, and a component of cold grains (15–25 K) is included. This versatile model allows for statistical constraints on star formation histories and dust contents of large galaxy samples using UV, optical, and infrared observations. The authors apply this model to 66 nearby star-forming galaxies from the Spitzer Infrared Nearby Galaxy Survey (SINGS) and find strong correlations between mid- and far-infrared colors and specific star formation rates, as well as other galaxy-wide properties. The model can be applied to interpret SEDs from any galaxy sample.