diff --git a/activesupport/lib/active_support/ordered_hash.rb b/activesupport/lib/active_support/ordered_hash.rb
index 8d1c0f51601e9..4324e40cbb1eb 100644
--- a/activesupport/lib/active_support/ordered_hash.rb
+++ b/activesupport/lib/active_support/ordered_hash.rb
@@ -12,11 +12,25 @@ def initialize(*args, &block)
 
       def self.[](*args)
         ordered_hash = new
-        args.each_with_index { |val,ind|
-          # Only every second value is a key.
-          next if ind % 2 != 0
+
+        if (args.length == 1 && args.first.is_a?(Array))
+          args.first.each do |key_value_pair|
+            next unless (key_value_pair.is_a?(Array))
+            ordered_hash[key_value_pair[0]] = key_value_pair[1]
+          end
+
+          return ordered_hash
+        end
+
+        unless (args.size % 2 == 0)
+          raise ArgumentError.new("odd number of arguments for Hash")
+        end
+
+        args.each_with_index do |val, ind|
+          next if (ind % 2 != 0)
           ordered_hash[val] = args[ind + 1]
-        }
+        end
+
         ordered_hash
       end
 
diff --git a/activesupport/test/ordered_hash_test.rb b/activesupport/test/ordered_hash_test.rb
index 647938dd87ae6..15bd57181f802 100644
--- a/activesupport/test/ordered_hash_test.rb
+++ b/activesupport/test/ordered_hash_test.rb
@@ -163,9 +163,32 @@ def test_inspect
     assert @ordered_hash.inspect.include?(@hash.inspect)
   end
 
-  def test_alternate_initialization
+  def test_alternate_initialization_with_splat
     alternate = ActiveSupport::OrderedHash[1,2,3,4]
     assert_kind_of ActiveSupport::OrderedHash, alternate
     assert_equal [1, 3], alternate.keys
   end
+
+  def test_alternate_initialization_with_array
+    alternate = ActiveSupport::OrderedHash[ [
+      [1, 2],
+      [3, 4],
+      "bad key value pair",
+      [ 'missing value' ]
+    ]]
+
+    assert_kind_of ActiveSupport::OrderedHash, alternate
+    assert_equal [1, 3, 'missing value'], alternate.keys
+    assert_equal [2, 4, nil ], alternate.values
+  end
+
+  def test_alternate_initialization_raises_exception_on_odd_length_args
+    begin
+      alternate = ActiveSupport::OrderedHash[1,2,3,4,5]
+      flunk "Hash::[] should have raised an exception on initialization " +
+          "with an odd number of parameters"
+    rescue
+      assert_equal "odd number of arguments for Hash", $!.message
+    end
+  end
 end