diff --git a/Gemfile b/Gemfile
index aed76b1..3a2a26f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,7 +5,7 @@ ruby '3.3.1'
 gem 'rest-client'
 
 group :development do
-  gem 'rdoc', '~> 3.12'
+  gem 'rdoc', '~> 6.1'
   gem 'bundler', '~> 2'
   gem 'jeweler', '~> 2'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index 6a91f8f..8cd26d9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -78,7 +78,6 @@ GEM
       rake
       rdoc
       semver
-    json (1.8.6)
     jwt (2.8.1)
       base64
     mime-types (3.5.2)
@@ -108,8 +107,7 @@ GEM
     rack (3.0.11)
     rake (13.2.1)
     rchardet (1.8.0)
-    rdoc (3.12.2)
-      json (~> 1.4)
+    rdoc (6.1.2.1)
     rest-client (2.1.0)
       http-accept (>= 1.7.0, < 2.0)
       http-cookie (>= 1.0.2, < 2.0)
@@ -149,7 +147,7 @@ PLATFORMS
 DEPENDENCIES
   bundler (~> 2)
   jeweler (~> 2)
-  rdoc (~> 3.12)
+  rdoc (~> 6.1)
   rest-client
   shoulda
   simplecov
diff --git a/languagetool.gemspec b/languagetool.gemspec
index 701df9a..a36c6ff 100644
--- a/languagetool.gemspec
+++ b/languagetool.gemspec
@@ -57,18 +57,18 @@ Gem::Specification.new do |s|
 
     if Gem::Version.new(Gem::VERSION) >= Gem::Version.new('1.2.0') then
       s.add_runtime_dependency(%q<rest-client>, [">= 0"])
-      s.add_development_dependency(%q<rdoc>, ["~> 3.12"])
+      s.add_development_dependency(%q<rdoc>, "~> 6.1")
       s.add_development_dependency(%q<bundler>, ["~> 1.0"])
       s.add_development_dependency(%q<jeweler>, ["~> 2.0.1"])
     else
       s.add_dependency(%q<rest-client>, [">= 0"])
-      s.add_dependency(%q<rdoc>, ["~> 3.12"])
+      s.add_dependency(%q<rdoc>, "~> 6.1")
       s.add_dependency(%q<bundler>, ["~> 1.0"])
       s.add_dependency(%q<jeweler>, ["~> 2.0.1"])
     end
   else
     s.add_dependency(%q<rest-client>, [">= 0"])
-    s.add_dependency(%q<rdoc>, ["~> 3.12"])
+    s.add_dependency(%q<rdoc>, "~> 6.1")
     s.add_dependency(%q<bundler>, ["~> 1.0"])
     s.add_dependency(%q<jeweler>, ["~> 2.0.1"])
   end