diff --git a/spack.yaml b/spack.yaml
index b54d57438e86d4ef6b87f32aca1d5436aeac546f..dbe74c2805d9d05b2dab83ca47a9ea6abd2c3529 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -62,7 +62,7 @@ spack:
     - py-uproot@4.3.5
     - py-yapf@0.30.0
     - qt@5.15.5 +opengl
-    - root@6.26.06 cxxstd=17 
+    - root@6.26.06 cxxstd=20 
           +fftw +fortran +gdml +http -ipo +mlp +pythia8 
           +root7 +tmva +vc -webgui +xrootd +ssl 
     - spdlog@1.10.0 +fmt_external