diff --git a/var/spack/repos/builtin/packages/hermes/package.py b/var/spack/repos/builtin/packages/hermes/package.py
index 69c984b3701..b7707c6648f 100644
--- a/var/spack/repos/builtin/packages/hermes/package.py
+++ b/var/spack/repos/builtin/packages/hermes/package.py
@@ -31,6 +31,7 @@ class Hermes(CMakePackage):
     depends_on("glog@0.4.0:")
     depends_on("mpi")
     depends_on("hdf5@1.13.0:", when="+vfd")
+    depends_on("yaml-cpp")
 
     def cmake_args(self):
         args = [