  Since the smallest leptonic mixing angle theta_{13} has been measured to be
relatively large, it is quite promising to constrain or determine the leptonic
Dirac CP-violating phase delta in future neutrino oscillation experiments.
Given some typical values of delta = pi/2, pi, and 3pi/2 at the low-energy
scale, as well as current experimental results of the other neutrino
parameters, we perform a systematic study of the radiative corrections to delta
by using the one-loop renormalization group equations in the minimal
supersymmetric standard model and the universal extra-dimensional model. It
turns out that delta is rather stable against radiative corrections in both
models, except for the minimal supersymmetric standard model with a very large
value of tan beta. Both cases of Majorana and Dirac neutrinos are discussed. In
addition, we use the preliminary indication of delta = (1.08^{+0.28}_{-0.31})
pi or delta = (1.67^{+0.37}_{-0.77}) pi from the latest global-fit analyses of
data from neutrino oscillation experiments to illustrate how it will be
modified by radiative corrections.
