The vacuum volatilization kinetics of Pb in In-Pb solder was investigated. The results indicate a significant increase in the vacuum volatilization rates of Pb, 25In-75Pb, 40In-60Pb, and In with increasing temperatures from 923 to 1123 K, system pressure of 3 Pa and holding time of 30 min. The mass transfer coefficients and apparent activation energies of Pb and its alloys were determined at various temperatures. Additionally, a kinetics model was developed to describe Pb vacuum volatilization in high-temperature melts. It is obtained that the vapor mass transfer is the factor limiting the vacuum volatilization rates of Pb and In–Pb alloys under the above specified conditions.