The electron and hole effective masses associated with the in-plane motion of an exciton in a quantum well are often derived from the Luttinger parameters associated with the bulk band structure. In this work empirical pseudo-potential calculations of the bulk band structure of CdTe including spin-orbit coupling are presented. For an exciton, mapping the real space in-plane motion of the electron and hole on to k-space allows the effective masses to be calculated from the pseudo-potential band structure at all points around the exciton orbit. The calculations reveal that for CdTe the in-plane masses of the electron, light- and heavy-hole are similar to those commonly accepted for motion along the growth or z-axis, i.e. 0.11, 0.15 and 0.45, respectively. The implications of these effective masses for exciton binding energies are discussed.