diff --git a/govuk_design_system_formbuilder.gemspec b/govuk_design_system_formbuilder.gemspec
index 52cde684..ad3b8dec 100644
--- a/govuk_design_system_formbuilder.gemspec
+++ b/govuk_design_system_formbuilder.gemspec
@@ -42,7 +42,7 @@ Gem::Specification.new do |s|
 
   # Required for the guide
   s.add_development_dependency("htmlbeautifier", "~> 1.4.1")
-  s.add_development_dependency("nanoc", "~> 4.12.15")
+  s.add_development_dependency("nanoc", "~> 4.13.0")
   s.add_development_dependency("rouge", "~> 4.2.0")
   s.add_development_dependency("rubypants", "~> 0.7.0")
   s.add_development_dependency("sass")