Femtosecond pulse propagation phenomena in semiconductors and semiconductor heterostructures are theoretically investigated. It is shown that the linear pulse propagation through a spatially inhomogeneous structure (multiple quantum wells) is substantially modified in comparison to the homogeneous case. For spatially homogeneous structures (bulk material), the nonlinear interplay between propagation and many‐body effects is investigated in four‐wave‐mixing geometry. For an inverted semiconductor collinear pump‐probe propagation is analyzed to study the ultrafast gain dynamics in amplifiers.