diff --git a/benchmark/path-manager.rb b/benchmark/path-manager.rb
new file mode 100644
index 00000000..969949fd
--- /dev/null
+++ b/benchmark/path-manager.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require 'benchmark/ips'
+require 'jekyll'
+
+class FooPage
+  def initialize(dir:, name:)
+    @dir = dir
+    @name = name
+  end
+
+  def slow_path
+    File.join(*[@dir, @name].map(&:to_s).reject(&:empty?)).sub(%r!\A/!, "")
+  end
+
+  def fast_path
+    Jekyll::PathManager.join(@dir, @name).sub(%r!\A/!, "")
+  end
+end
+
+nil_page     = FooPage.new(:dir => nil, :name => nil)
+empty_page   = FooPage.new(:dir => "", :name => "")
+root_page    = FooPage.new(:dir => "", :name => "ipsum.md")
+nested_page  = FooPage.new(:dir => "lorem", :name => "ipsum.md")
+slashed_page = FooPage.new(:dir => "/lorem/", :name => "/ipsum.md")
+
+if nil_page.slow_path == nil_page.fast_path
+  Benchmark.ips do |x|
+    x.report('nil_page slow') { nil_page.slow_path }
+    x.report('nil_page fast') { nil_page.fast_path }
+    x.compare!
+  end
+end
+
+if empty_page.slow_path == empty_page.fast_path
+  Benchmark.ips do |x|
+    x.report('empty_page slow') { empty_page.slow_path }
+    x.report('empty_page fast') { empty_page.fast_path }
+    x.compare!
+  end
+end
+
+if root_page.slow_path == root_page.fast_path
+  Benchmark.ips do |x|
+    x.report('root_page slow') { root_page.slow_path }
+    x.report('root_page fast') { root_page.fast_path }
+    x.compare!
+  end
+end
+
+if nested_page.slow_path == nested_page.fast_path
+  Benchmark.ips do |x|
+    x.report('nested_page slow') { nested_page.slow_path }
+    x.report('nested_page fast') { nested_page.fast_path }
+    x.compare!
+  end
+end
+
+if slashed_page.slow_path == slashed_page.fast_path
+  Benchmark.ips do |x|
+    x.report('slashed_page slow') { slashed_page.slow_path }
+    x.report('slashed_page fast') { slashed_page.fast_path }
+    x.compare!
+  end
+end
diff --git a/lib/jekyll/page.rb b/lib/jekyll/page.rb
index 20eefe96..a9ba4e37 100644
--- a/lib/jekyll/page.rb
+++ b/lib/jekyll/page.rb
@@ -121,6 +121,8 @@ module Jekyll
     # NOTE: `String#gsub` removes all trailing periods (in comparison to `String#chomp`)
     # Returns nothing.
     def process(name)
+      return unless name
+
       self.ext = File.extname(name)
       self.basename = name[0..-ext.length - 1].gsub(%r!\.*\z!, "")
     end
@@ -147,7 +149,7 @@ module Jekyll
 
     # The path to the page source file, relative to the site source
     def relative_path
-      @relative_path ||= File.join(*[@dir, @name].map(&:to_s).reject(&:empty?)).sub(%r!\A/!, "")
+      @relative_path ||= PathManager.join(@dir, @name).sub(%r!\A/!, "")
     end
 
     # Obtain destination path.
diff --git a/test/test_page_without_a_file.rb b/test/test_page_without_a_file.rb
index 2665696f..855719aa 100644
--- a/test/test_page_without_a_file.rb
+++ b/test/test_page_without_a_file.rb
@@ -28,6 +28,21 @@ class TestPageWithoutAFile < JekyllUnitTest
                        ))
     end
 
+    should "have non-frozen path and relative_path attributes" do
+      {
+        ["foo", "bar.md"]     => "foo/bar.md",
+        [nil, nil]            => "",
+        ["", ""]              => "",
+        ["/lorem/", "/ipsum"] => "lorem/ipsum",
+        %w(lorem ipsum)       => "lorem/ipsum",
+      }.each do |(dir, name), result|
+        page = PageWithoutAFile.new(@site, @site.source, dir, name)
+        assert_equal result, page.path
+        assert_equal result, page.relative_path
+        refute page.relative_path.frozen?
+      end
+    end
+
     context "with default site configuration" do
       setup do
         @page = setup_page("properties.html")