diff --git a/doc/src/Developer_code_design.rst b/doc/src/Developer_code_design.rst
index ca4d66fb1f..820ad47fba 100644
--- a/doc/src/Developer_code_design.rst
+++ b/doc/src/Developer_code_design.rst
@@ -255,7 +255,7 @@ class.
    #undef PairStyle
    #undef PAIR_CLASS
 
-   // from pair_lj_cut.cpp
+   // from pair_lj_cut.h
 
    #ifdef PAIR_CLASS
    PairStyle(lj/cut,PairLJCut);