diff --git a/requirements.txt b/requirements.txt
index 389c862..ade7f69 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -32,6 +32,7 @@
 treq>=15.1.0
 Twisted>=13.2.0
 urllib3>=1.7.1
+pyang>=1.7
 
 # python-consul>=0.6.1  we need the pre-released version for now, because 0.6.1 does not
 # yet support Twisted. Once this is released, it will be the 0.6.2 version