A variable turbulent Prandtl number model is applied to the prediction of laboratory jets with signie cant temperature variations. The model involves solving supplemental scalar equations for the temperature variance anditsdissipationratealongwiththe k‐"equations.Themodelisalsoappliedtojetswithvariablecompositionwith the aim of building a consolidated approach to model e uctuations of both temperature and species mass fraction. Comparisons are presented for subsonic jets for which scalar e uctuation measurements are available. The same coefe cientsareusedfortemperature/speciesvarianceanddissipationrateequations.Excellentagreementwithdata isobtained forround jets with respect to scalare uctuation intensitiesand prediction of turbulent Prandtl/Schmidt numbers.