diff --git a/lib/rubygems/commands/install_command.rb b/lib/rubygems/commands/install_command.rb
index 70d32013ba6a..c615f6329e94 100644
--- a/lib/rubygems/commands/install_command.rb
+++ b/lib/rubygems/commands/install_command.rb
@@ -159,6 +159,10 @@ def execute
 
     load_hooks
 
+    if ENV["GEM_HOST_API_KEY"]
+      Gem::RemoteFetcher.fetcher.headers[:authorization] = ENV["GEM_HOST_API_KEY"]
+    end
+
     exit_code = install_gems
 
     show_installed
diff --git a/test/rubygems/test_gem_commands_install_command.rb b/test/rubygems/test_gem_commands_install_command.rb
index d2ca933a632c..5d0b1c6541d8 100644
--- a/test/rubygems/test_gem_commands_install_command.rb
+++ b/test/rubygems/test_gem_commands_install_command.rb
@@ -26,6 +26,10 @@ def teardown
     Gem::Command.build_args = @orig_args
     File.unlink @gemdeps if File.file? @gemdeps
     File.unlink "#{@gemdeps}.lock" if File.file? "#{@gemdeps}.lock"
+
+    if defined? Gem::RemoteFetcher
+      Gem::RemoteFetcher.fetcher = nil
+    end
   end
 
   def test_execute_exclude_prerelease
@@ -737,6 +741,22 @@ def test_execute_remote
     assert_match "1 gem installed", @ui.output
   end
 
+  def test_execute_remote_gem_host_api_key
+    Gem::RemoteFetcher.fetcher = @fetcher = Gem::FakeFetcher.new
+    @a1, @a1_gem = util_gem "a", "1"
+    util_setup_spec_fetcher @a1
+    @fetcher.data["http://gems.example.com/gems/a-1.gem"] = Gem.read_binary(@a1_gem)
+
+    ENV["GEM_HOST_API_KEY"] = "temporary_secret_key"
+    @cmd.options[:args] = %w[a]
+    use_ui @stub_ui do
+      @cmd.execute
+    end
+
+    assert_match "1 gem installed", @ui.output
+    assert_equal "temporary_secret_key", @fetcher.headers[:authorization]
+  end
+
   def test_execute_with_invalid_gem_file
     FileUtils.touch("a.gem")
 
diff --git a/test/rubygems/utilities.rb b/test/rubygems/utilities.rb
index bf601f6fac2d..28b02346a56d 100644
--- a/test/rubygems/utilities.rb
+++ b/test/rubygems/utilities.rb
@@ -30,11 +30,12 @@
 # See RubyGems' tests for more examples of FakeFetcher.
 
 class Gem::FakeFetcher
-  attr_reader :data, :requests
+  attr_reader :data, :headers, :requests
   attr_accessor :paths
 
   def initialize
     @data = {}
+    @headers = {}
     @paths = []
     @requests = []
   end