diff --git a/docs/environment.yml b/docs/environment.yml
index 8f49d550..1b971544 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -5,5 +5,6 @@ channels:
 
 dependencies:
   - breathe
+  - graphviz
   - pip:
-    - sphinx_rtd_theme
\ No newline at end of file
+    - sphinx_rtd_theme