diff --git a/setup.cfg b/setup.cfg
index a5da0f0..5d4c384 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,6 +31,7 @@ install_requires =
     rxn-reaction-preprocessing>=2.0.2
     rxn-utils>=1.1.9
     rxn-onmt-utils @ git+https://github.com/rxn4chemistry/rxn-onmt-utils.git@c8591b42bf04400e6c6c5847d5edb3326481ba34 #rxn-onmt-utils without rxn-opennmt-py depedency
+    OpenNMT-py>=3.5.1 # official onmt
 
 [options.packages.find]
 where = src