diff --git a/tox.ini b/tox.ini
index 9c43776a2c2..843a0680ed9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@ envlist =
     py3{7,8,9,10,11}-opentelemetry-api
     pypy3-opentelemetry-api
 
-	  ; Test against both protobuf 3.x and 4.x
+    ; Test against both protobuf 3.x and 4.x
     py3{7,8,9,10,11}-proto{3,4}-opentelemetry-protobuf
     pypy3-proto{3,4}-opentelemetry-protobuf