The mechanical properties of the lung periphery are vital to the overall function of the whole organ, and play a key role in the symptomatology of many lung diseases. We first review the experimental methodologies that have been used to investigate peripheral lung mechanics, including the retrograde catheter, the alveolar capsule, the alveolar capsule oscillator, and the forced oscillation technique. We then discuss the interpretation of the data provided by these techniques in terms of inverse mathematical models of the lung, including the constant-phase model. Finally, we describe efforts to construct anatomically accurate forward models of the lung based on data from imaging modalities such as computed tomography and magnetic resonance imaging. Together, these various approaches have provided a great deal of information about the relative importance of the lung periphery in mechanical function in animal models of lung disease and in human patients. An increasing body of evidence indicates that constriction in this part of the lung is a crucial determinant of the severity of asthma.