diff --git a/.gitignore b/.gitignore
index 728456b5f2..0a7ed12aff 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@
 # Ignore Bundler files
 **/.bundle/bin
 **/.bundle/cache
+**/vendor/bundle/ruby/*/bundler.lock
 **/vendor/bundle/ruby/*/bin
 **/vendor/bundle/ruby/*/build_info/
 **/vendor/bundle/ruby/*/cache
diff --git a/Library/Homebrew/dev-cmd/vendor-gems.rb b/Library/Homebrew/dev-cmd/vendor-gems.rb
index 9f028e5dc7..9ff4e6ed52 100644
--- a/Library/Homebrew/dev-cmd/vendor-gems.rb
+++ b/Library/Homebrew/dev-cmd/vendor-gems.rb
@@ -18,17 +18,28 @@ module Homebrew
         Install and commit Homebrew's vendored gems.
       EOS
 
+      switch "--update",
+             description: "Update all vendored Gems to the latest version."
+
       max_named 0
     end
   end
 
   def vendor_gems
-    vendor_gems_args.parse
+    args = vendor_gems_args.parse
 
     Homebrew.install_bundler!
 
     ohai "cd #{HOMEBREW_LIBRARY_PATH}"
     HOMEBREW_LIBRARY_PATH.cd do
+      if args.update?
+        ohai "bundle update"
+        safe_system "bundle", "update"
+
+        ohai "git add Gemfile.lock"
+        system "git", "add", "Gemfile.lock"
+      end
+
       ohai "bundle install --standalone"
       safe_system "bundle", "install", "--standalone"
 
diff --git a/docs/Manpage.md b/docs/Manpage.md
index cb9af56786..8bc56518e8 100644
--- a/docs/Manpage.md
+++ b/docs/Manpage.md
@@ -1339,6 +1339,9 @@ If no options are passed, use `origin/master` as the start commit.
 
 Install and commit Homebrew's vendored gems.
 
+* `--update`:
+  Update all vendored Gems to the latest version.
+
 ## GLOBAL CASK OPTIONS
 
 These options are applicable to subcommands accepting a `--cask` flag and all `cask` commands.
diff --git a/manpages/brew.1 b/manpages/brew.1
index 5dcb13e59f..ec68ae005e 100644
--- a/manpages/brew.1
+++ b/manpages/brew.1
@@ -1851,6 +1851,10 @@ Use the commit at the specified \fIdate\fR as the start commit\.
 .SS "\fBvendor\-gems\fR"
 Install and commit Homebrew\'s vendored gems\.
 .
+.TP
+\fB\-\-update\fR
+Update all vendored Gems to the latest version\.
+.
 .SH "GLOBAL CASK OPTIONS"
 These options are applicable to subcommands accepting a \fB\-\-cask\fR flag and all \fBcask\fR commands\.
 .