diff --git a/Gemfile b/Gemfile
index f81869344cb..99c0e92f845 100644
--- a/Gemfile
+++ b/Gemfile
@@ -30,7 +30,10 @@ group :test do
   gem "test-theme-skinny", :path => File.expand_path("test/fixtures/test-theme-skinny", __dir__)
   gem "test-theme-symlink", :path => File.expand_path("test/fixtures/test-theme-symlink", __dir__)
 
-  gem "jruby-openssl" if RUBY_ENGINE == "jruby"
+  if RUBY_ENGINE == "jruby"
+    gem "http_parser.rb", "~> 0.6.0"
+    gem "jruby-openssl"
+  end
 end
 
 #
diff --git a/History.markdown b/History.markdown
index 94a5303da02..74e5f9c1ac6 100644
--- a/History.markdown
+++ b/History.markdown
@@ -1,3 +1,9 @@
+## HEAD
+
+### Bug Fixes
+
+  * Lock `http_parser.rb` gem to `v0.6.x` on JRuby.
+
 ## 4.2.1 / 2021-09-27
 
 ### Bug Fixes
diff --git a/lib/jekyll/commands/new.rb b/lib/jekyll/commands/new.rb
index 4623ddafba4..150b4aa7360 100644
--- a/lib/jekyll/commands/new.rb
+++ b/lib/jekyll/commands/new.rb
@@ -99,6 +99,9 @@ def gemfile_contents
             # Performance-booster for watching directories on Windows
             gem "wdm", "~> 0.1.1", :platforms => [:mingw, :x64_mingw, :mswin]
 
+            # Lock `http_parser.rb` gem to `v0.6.x` on JRuby builds since newer versions of the gem
+            # do not have a Java counterpart.
+            gem "http_parser.rb", "~> 0.6.0", :platforms => [:jruby]
           RUBY
         end