diff --git a/var/spack/repos/builtin/packages/trilinos/package.py b/var/spack/repos/builtin/packages/trilinos/package.py
index d84b8554f2e..65b011b0f2c 100644
--- a/var/spack/repos/builtin/packages/trilinos/package.py
+++ b/var/spack/repos/builtin/packages/trilinos/package.py
@@ -331,6 +331,7 @@ class Trilinos(CMakePackage, CudaPackage, ROCmPackage):
     )
     conflicts("+adios2", when="@:12.14.1")
     conflicts("cxxstd=11", when="@13.2:")
+    conflicts("cxxstd=14", when="@14:")
     conflicts("cxxstd=17", when="@:12")
     conflicts("cxxstd=11", when="+wrapper ^cuda@6.5.14")
     conflicts("cxxstd=14", when="+wrapper ^cuda@6.5.14:8.0.61")