diff --git a/include/openmc/source.h b/include/openmc/source.h
index 47761ff8cb..97b18d2286 100644
--- a/include/openmc/source.h
+++ b/include/openmc/source.h
@@ -71,7 +71,7 @@ Particle::Bank sample_custom_source_library(uint64_t* seed);
 //! Load custom source library
 void load_custom_source_library();
 
-//Release custom source library
+//! Release custom source library
 void close_custom_source_library();
 
 //! Fill source bank at the end of a generation for dlopen based source simulation