diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 8c424e1754d7..2b2c11492614 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -8,21 +8,26 @@
 
 # main C++ code
 include/*    @guolinke @chivee
+src/*    @guolinke @chivee
 CmakeLists.txt    @guolinke @chivee @Laurae2 @jameslamb @wxchan @henry0312 @StrikerRUS @huanzhang12
 
 # R code
+include/LightGBM/lightgbm_R.h    @Laurae2 @jameslamb
+include/LightGBM/R_object_helper.h    @Laurae2 @jameslamb
+src/lightgbm_R.cpp    @Laurae2 @jameslamb
 R-package/*    @Laurae2 @jameslamb
 *.R    @Laurae2 @jameslamb
 
 # Python code
-python-package/*    @StrikerRUS @chivee
-*.py    @StrikerRUS @wxchan @henry0312
+python-package/*    @StrikerRUS @chivee @wxchan @henry0312
+
+# helpers
+helpers/*    @StrikerRUS @guolinke
 
 # CI administrative stuff
 .ci/*    @StrikerRUS @Laurae2 @jameslamb
 docs/*    @StrikerRUS @Laurae2 @jameslamb
-.travis.yml    @StrikerRUS @Laurae2 @jameslamb
-.appveyor.yml    @StrikerRUS @Laurae2 @jameslamb
+*.yml    @StrikerRUS @Laurae2 @jameslamb
 .vsts-ci.yml    @Laurae2
 
 # GPU code