diff --git a/src/mlpack/core/dists/regression_distribution.hpp b/src/mlpack/core/dists/regression_distribution.hpp
index c306b030eb..e109a142fb 100644
--- a/src/mlpack/core/dists/regression_distribution.hpp
+++ b/src/mlpack/core/dists/regression_distribution.hpp
@@ -18,7 +18,7 @@
 #include <mlpack/methods/linear_regression/linear_regression.hpp>
 
 namespace mlpack {
-namespace distribution {
+namespace distribution /** Probability distributions. */ {
 
 /**
  * A class that represents a univariate conditionally Gaussian distribution.