Inverse Compton scattering, wherein a photon gains energy as a result of a reaction with a moving electron, has been studied as a potential energy loss mechanism in the operation of a controlled thermonuclear reactor (CTR). Assuming local thermodynamic equilibrium within a 500-cm-diam plasma at 20 keV we have calculated, for various plasma densities, the influence of inverse Compton scattering on steady-state photon energy leakage via two potential cooling effects: the increased escape probability of the photons generated within the plasma itself, and the negative net energy deposition within the plasma of an incident external photon flux, such as might be generated by the CTR radiation shield through (n,γ) reactions and photon scattering. For currently anticipated CTR plasma densities (1015 ions/cm3), the increase in steady-state photon leakage due to inverse Compton scattering is negligible. For plasma densities of 1019 ions/cm3 or more, the increase is significant (≥10%).