diff --git a/lib/jekyll/configuration.rb b/lib/jekyll/configuration.rb
index 2931cba4500..a9965d29f5b 100644
--- a/lib/jekyll/configuration.rb
+++ b/lib/jekyll/configuration.rb
@@ -156,7 +156,7 @@ def config_files(override)
       )
 
       # Get configuration from <source>/_config.yml or <source>/<config_file>
-      config_files = override.delete("config")
+      config_files = override["config"]
       if config_files.to_s.empty?
         default = %w(yml yaml).find(-> { "yml" }) do |ext|
           File.exist?(Jekyll.sanitized_path(source(override), "_config.#{ext}"))
diff --git a/lib/jekyll/drops/site_drop.rb b/lib/jekyll/drops/site_drop.rb
index cb4a007eb15..20b0332a43c 100644
--- a/lib/jekyll/drops/site_drop.rb
+++ b/lib/jekyll/drops/site_drop.rb
@@ -38,6 +38,9 @@ def collections
         @site_collections ||= @obj.collections.values.sort_by(&:label).map(&:to_liquid)
       end
 
+      # return nil for `{{ site.config }}` even if --config was passed via CLI
+      def config; end
+
       private
       def_delegator :@obj, :config, :fallback_data
     end
diff --git a/test/test_configuration.rb b/test/test_configuration.rb
index dddb61b8671..3dbd5ca1c4e 100644
--- a/test/test_configuration.rb
+++ b/test/test_configuration.rb
@@ -356,7 +356,10 @@ class TestConfiguration < JekyllUnitTest
         .and_return({ "baseurl" => "http://example.com" })
       allow($stdout).to receive(:puts).with("Configuration file: #{@paths[:other]}")
       assert_equal \
-        site_configuration({ "baseurl" => "http://example.com" }),
+        site_configuration({
+          "baseurl" => "http://example.com",
+          "config"  => @paths[:other],
+        }),
         Jekyll.configuration(test_config.merge({ "config" => @paths[:other] }))
     end
 
@@ -368,7 +371,10 @@ class TestConfiguration < JekyllUnitTest
         .and_return({ "baseurl" => "http://example.com" })
       allow($stdout).to receive(:puts).with("Configuration file: #{@paths[:other]}")
       assert_equal \
-        site_configuration({ "baseurl" => "http://example.com" }),
+        site_configuration({
+          "baseurl" => "http://example.com",
+          "config"  => @paths[:other],
+        }),
         Jekyll.configuration(test_config.merge({ :config => @paths[:other] }))
     end
 
@@ -376,15 +382,18 @@ class TestConfiguration < JekyllUnitTest
       allow(SafeYAML).to receive(:load_file).with(@paths[:default]).and_return({})
       allow($stdout).to receive(:puts).with("Configuration file: #{@paths[:default]}")
       assert_equal \
-        site_configuration,
+        site_configuration({ "config" => [@paths[:empty]] }),
         Jekyll.configuration(test_config.merge({ "config" => [@paths[:empty]] }))
     end
 
     should "successfully load a TOML file" do
       Jekyll.logger.log_level = :warn
       assert_equal \
-        site_configuration({ "baseurl" => "/you-beautiful-blog-you",
-                             "title"   => "My magnificent site, wut", }),
+        site_configuration({
+          "baseurl" => "/you-beautiful-blog-you",
+          "title"   => "My magnificent site, wut",
+          "config"  => [@paths[:toml]],
+        }),
         Jekyll.configuration(test_config.merge({ "config" => [@paths[:toml]] }))
       Jekyll.logger.log_level = :info
     end
@@ -399,7 +408,9 @@ class TestConfiguration < JekyllUnitTest
       allow($stdout).to receive(:puts).with("Configuration file: #{@paths[:other]}")
       allow($stdout).to receive(:puts).with("Configuration file: #{@paths[:toml]}")
       assert_equal(
-        site_configuration,
+        site_configuration({
+          "config" => [@paths[:default], @paths[:other], @paths[:toml]],
+        }),
         Jekyll.configuration(
           test_config.merge(
             { "config" => [@paths[:default], @paths[:other], @paths[:toml]] }
@@ -424,7 +435,10 @@ class TestConfiguration < JekyllUnitTest
         .to receive(:puts)
         .with("Configuration file: #{@paths[:other]}")
       assert_equal \
-        site_configuration({ "baseurl" => "http://example.com" }),
+        site_configuration({
+          "baseurl" => "http://example.com",
+          "config"  => [@paths[:default], @paths[:other]],
+        }),
         Jekyll.configuration(
           test_config.merge({ "config" => [@paths[:default], @paths[:other]] })
         )