In a recent re-analysis of the Standard Model (SM) (β)-function for the effective neutrino mass operator, we found that the previous results were not entirely correct. Therefore, we consider the analogous dimension five operators in a class of two Higgs doublet models (2HDM's) and the minimal supersymmetric Standard Model (MSSM). Deriving the renormalization group equations for these effective operators, we confirm the existing result in the case of the MSSM. Some of our 2HDM results are new, while others differ from earlier calculations. This leads to modifications in the renormalization group evolution of leptonic mixing angles and CP phases in the 2HDM's. © 2002 Elsevier Science B.V. All rights reserved.