diff --git a/requirements.txt b/requirements.txt
index 2ece8cf8..d283dec0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,9 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 Babel!=2.4.0,>=2.3.4 # BSD
-networkx>=1.10 # BSD
+# NOTE(fdegir): NetworkX 2.3 dropped support for Python 2
+networkx>=1.10,<2.3;python_version<'3.0' # BSD
+networkx>=1.10;python_version>='3.4' # BSD
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 PyYAML>=3.12 # MIT
 flake8<2.6.0,>=2.5.4 # MIT