diff --git a/requirements.txt b/requirements.txt
index 1e3b339884..96cb4fb030 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,7 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
 dnspython>=1.9.4
 eventlet>=0.9.15
 greenlet>=0.3.1
diff --git a/test-requirements.txt b/test-requirements.txt
index a5a7118995..8c617baacb 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -1,3 +1,7 @@
+# The order of packages is significant, because pip processes them in the order
+# of appearance. Changing the order has an impact on the overall integration
+# process, which may cause wedges in the gate later.
+
 # Hacking already pins down pep8, pyflakes and flake8
 hacking>=0.8.0,<0.9
 coverage