diff --git a/hash.c b/hash.c
index 7568538214..1c36a22bc0 100644
--- a/hash.c
+++ b/hash.c
@@ -6589,10 +6589,12 @@ env_update_block_i(VALUE key, VALUE val, VALUE _)
 
 /*
  * call-seq:
- *   ENV.update(hash)                                     -> ENV
- *   ENV.update(hash) { |name, env_val, hash_val| block } -> ENV
- *   ENV.merge!(hash)                                     -> ENV
- *   ENV.merge!(hash) { |name, env_val, hash_val| block } -> ENV
+ *   ENV.update                                              -> ENV
+ *   ENV.update(*hashes)                                     -> ENV
+ *   ENV.update(*hashes) { |name, env_val, hash_val| block } -> ENV
+ *   ENV.merge!                                              -> ENV
+ *   ENV.merge!(*hashes)                                     -> ENV
+ *   ENV.merge!(*hashes) { |name, env_val, hash_val| block } -> ENV
  *
  * ENV.update is an alias for ENV.merge!.
  *
@@ -6624,13 +6626,16 @@ env_update_block_i(VALUE key, VALUE val, VALUE _)
  * those following are ignored.
  */
 static VALUE
-env_update(VALUE env, VALUE hash)
+env_update(int argc, VALUE *argv, VALUE env)
 {
-    if (env == hash) return env;
-    hash = to_hash(hash);
     rb_foreach_func *func = rb_block_given_p() ?
         env_update_block_i : env_update_i;
-    rb_hash_foreach(hash, func, 0);
+    for (int i = 0; i < argc; ++i) {
+        VALUE hash = argv[i];
+        if (env == hash) continue;
+        hash = to_hash(hash);
+        rb_hash_foreach(hash, func, 0);
+    }
     return env;
 }
 
@@ -7458,8 +7463,8 @@ Init_Hash(void)
     rb_define_singleton_method(envtbl, "freeze", env_freeze, 0);
     rb_define_singleton_method(envtbl, "invert", env_invert, 0);
     rb_define_singleton_method(envtbl, "replace", env_replace, 1);
-    rb_define_singleton_method(envtbl, "update", env_update, 1);
-    rb_define_singleton_method(envtbl, "merge!", env_update, 1);
+    rb_define_singleton_method(envtbl, "update", env_update, -1);
+    rb_define_singleton_method(envtbl, "merge!", env_update, -1);
     rb_define_singleton_method(envtbl, "inspect", env_inspect, 0);
     rb_define_singleton_method(envtbl, "rehash", env_none, 0);
     rb_define_singleton_method(envtbl, "to_a", env_to_a, 0);
diff --git a/spec/ruby/core/env/shared/update.rb b/spec/ruby/core/env/shared/update.rb
index 2746e86545..1142c503b8 100644
--- a/spec/ruby/core/env/shared/update.rb
+++ b/spec/ruby/core/env/shared/update.rb
@@ -15,6 +15,15 @@ describe :env_update, shared: true do
     ENV["bar"].should == "1"
   end
 
+  ruby_version_is "3.1" do
+    it "adds the multiple parameter hashes to ENV, returning ENV" do
+      ENV.send(@method, {"foo" => "0", "bar" => "1"}, {"baz" => "2"}).should equal(ENV)
+      ENV["foo"].should == "0"
+      ENV["bar"].should == "1"
+      ENV["baz"].should == "2"
+    end
+  end
+
   it "returns ENV when no block given" do
     ENV.send(@method, {"foo" => "0", "bar" => "1"}).should equal(ENV)
   end
diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index 87ccd5102b..e9eaf144a1 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -494,12 +494,20 @@ class TestEnv < Test::Unit::TestCase
     ENV["baz"] = "qux"
     ENV.update({"baz"=>"quux","a"=>"b"})
     check(ENV.to_hash.to_a, [%w(foo bar), %w(baz quux), %w(a b)])
+    ENV.update
+    check(ENV.to_hash.to_a, [%w(foo bar), %w(baz quux), %w(a b)])
+    ENV.update({"foo"=>"zot"}, {"c"=>"d"})
+    check(ENV.to_hash.to_a, [%w(foo zot), %w(baz quux), %w(a b), %w(c d)])
 
     ENV.clear
     ENV["foo"] = "bar"
     ENV["baz"] = "qux"
     ENV.update({"baz"=>"quux","a"=>"b"}) {|k, v1, v2| k + "_" + v1 + "_" + v2 }
     check(ENV.to_hash.to_a, [%w(foo bar), %w(baz baz_qux_quux), %w(a b)])
+    ENV.update {|k, v1, v2| k + "_" + v1 + "_" + v2 }
+    check(ENV.to_hash.to_a, [%w(foo bar), %w(baz baz_qux_quux), %w(a b)])
+    ENV.update({"foo"=>"zot"}, {"c"=>"d"}) {|k, v1, v2| k + "_" + v1 + "_" + v2 }
+    check(ENV.to_hash.to_a, [%w(foo foo_bar_zot), %w(baz baz_qux_quux), %w(a b), %w(c d)])
   end
 
   def test_huge_value