diff --git a/CHANGELOG.md b/CHANGELOG.md
index 24acb86f..c33a1099 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+## [2.66.0] - 2026-01-10
+
 - Support `mdbook-mermaid-ssr`. ([#1400](https://github.com/taiki-e/install-action/pull/1400), thanks @CommanderStorm)
 
 - Improve support for Windows with MSYS2 bash.
@@ -5315,7 +5317,8 @@ Note: This release is considered a breaking change because installing on version
 
 Initial release
 
-[Unreleased]: https://github.com/taiki-e/install-action/compare/v2.65.16...HEAD
+[Unreleased]: https://github.com/taiki-e/install-action/compare/v2.66.0...HEAD
+[2.66.0]: https://github.com/taiki-e/install-action/compare/v2.65.16...v2.66.0
 [2.65.16]: https://github.com/taiki-e/install-action/compare/v2.65.15...v2.65.16
 [2.65.15]: https://github.com/taiki-e/install-action/compare/v2.65.14...v2.65.15
 [2.65.14]: https://github.com/taiki-e/install-action/compare/v2.65.13...v2.65.14