diff --git a/docs/source/tools/castool.rst b/docs/source/tools/castool.rst
index a84742f96e8..b4d8f81467f 100644
--- a/docs/source/tools/castool.rst
+++ b/docs/source/tools/castool.rst
@@ -1,5 +1,5 @@
-Castool - *A generic casette image manipulation tool for MAME*
-==============================================================
+Castool - *A generic cassette image manipulation tool for MAME*
+===============================================================