We study the triply heavy baryons ΩQQQ (Q =c,b) in the QCD sum rules by performing the first calcu-lation of the next-to-leading order (NLO) contribution to the perturbative QCD part of the correlation functions.Compared with the leading order (LO) result,the NLO contribution is found to be very important to the ΩQQQ.This is because the NLO not only results in a large correction but also reduces the parameter dependence,making the Borel platform more distinct,especially for the Ωbbb in the MS scheme,where the platform appears only at NLO but not at LO.Particularly,owing to the inclusion of the NLO contribution,the renormalization schemes (MS and On-Shell) dependence and the scale dependence are significantly reduced.Consequently,after including the NLO contri-bution to the perturbative part in the QCD sum rules,the masses are estimated to be 4053+0.26-0.11 GeV for Ωccc and 4.97+0.33-0.32 GeV for Ωbbb,where the results are obtained atμ =MB with errors including those from the variation of the renormalization scaleμ in the range (0.8-1.2)MB.A careful study of the μ dependence in a wider range is fur-ther performed,which shows that the LO results are very sensitive to the choice ofμ whereas the NLO results are considerably better.In addition to theμ =MB result,a more stable value,(4.75-4.80) GeV,for the Ωc.c.c mass is found in the range of μ =(1.2-2.0)MB,which should be viewed as a more relevant prediction in our NLO ap-proach because ofμ dependence.