diff --git a/constraints.txt b/constraints.txt
index de32e30..6fd0ed2 100644
--- a/constraints.txt
+++ b/constraints.txt
@@ -60,7 +60,7 @@ wheel>=0.40.0,<1.0.0
 
 # Documentation
 sphinx>=7.0.0,<10.0.0
-sphinx-rtd-theme>=1.3.0,<4.0.0
+sphinx-rtd-theme>=3.1.0,<4.0.0
 
 # Development utilities
 tox>=4.0.0,<5.0.0