Sintering can be modeled macroscopically as the high-temperature deformation of a homogeneous continuum, although microstructure evolution is complex and heterogeneous at the particle scale. The macroscopic strain rate is expressed as a linear response to the sintering stress and the macroscopic mechanical stress defined in a representative volume element. The sintering stress and the macroscopic viscosities, which can be measured experimentally, depend on microstructures, relative density, and grain size. The continuum mechanics of sintering is utilized to predict the shape distortion of components due to inhomogeneous density distribution. The model elucidates how defects are formed from localized inhomogeneities during sintering. The analysis based on continuum theory is applied to the constrained sintering, co-sintering of laminates, and sintering of composites. When the anisotropic microstructure develops during sintering, it is essential to use anisotropic constitutive equations.