diff --git a/src/main/scala/scalatutorial/sections/PolymorphicTypes.scala b/src/main/scala/scalatutorial/sections/PolymorphicTypes.scala
index eb39cdd9..2425d0b9 100644
--- a/src/main/scala/scalatutorial/sections/PolymorphicTypes.scala
+++ b/src/main/scala/scalatutorial/sections/PolymorphicTypes.scala
@@ -328,7 +328,7 @@ object PolymorphicTypes extends ScalaTutorialSection {
    * }}}
    *
    * In such a case, intuitively, it makes sense to have `Vet[Mammal] <: Vet[Zebra]` because
-   * a vet that can treat any mammal is able to to treat a zebra in particular. This is
+   * a vet that can treat any mammal is able to treat a zebra in particular. This is
    * an example of a contravariant type.
    *
    * == Variance Checks ==