diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 33796ea9a66..a7adde030a9 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -34,8 +34,16 @@ def initialize(*args)
       super
 
       custom_gemfile = options[:gemfile] || Bundler.settings[:gemfile]
+
+      if ENV["BUNDLE_GEMFILE"] && !ENV["BUNDLE_GEMFILE"].empty?
+        custom_gemfile = ENV["BUNDLE_GEMFILE"]
+      end
+
       if custom_gemfile && !custom_gemfile.empty?
-        Bundler::SharedHelpers.set_env "BUNDLE_GEMFILE", File.expand_path(custom_gemfile)
+        unless ENV["BUNDLE_GEMFILE"]
+          Bundler::SharedHelpers.set_env "BUNDLE_GEMFILE", File.expand_path(custom_gemfile)
+        end
+
         Bundler.reset_paths!
       end