I will first discuss the general manner in which computations of electroweak reactions on deuterium are carried out. Such calculations require knowledge of both the NN potential that is used to generate the deuteron wave function, and the operator which governs the interaction of the deuteron's constituent nucleons with the external probe. I will then introduce chiral perturbation theory, and argue that this effective field theory provides a systematic and reliable technique by which both the NN potential and operators for electroweak processes can be computed. I will display two examples of calculations of that character that I have been involved in: elastic electron-deuteron scattering, and Compton scattering on deuterium. The results of these callculations demonstrate that effective field theories can be used to reliably compute operators and wave functions for low-momentum-transfer reactions in light nuclear systems.