diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index b1c303e435..ac27dc640e 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Encoding ActiveSupport::TimeWithZone to YAML now preserves the timezone information.
+
+    Fixes #9183.
+
+    *Andrew White*
+
 *   Added `ActiveSupport::TimeZone#strptime` to allow parsing times as if
     from a given timezone.
 
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index c28de4e21c..b0d7f3299f 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -169,12 +169,13 @@ module ActiveSupport
       end
     end
 
-    def encode_with(coder)
-      if coder.respond_to?(:represent_object)
-        coder.represent_object(nil, utc)
-      else
-        coder.represent_scalar(nil, utc.strftime("%Y-%m-%d %H:%M:%S.%9NZ"))
-      end
+    def init_with(coder) #:nodoc:
+      initialize(coder['utc'], coder['zone'], coder['time'])
+    end
+
+    def encode_with(coder) #:nodoc:
+      coder.tag = '!ruby/object:ActiveSupport::TimeWithZone'
+      coder.map = { 'utc' => utc, 'zone' => time_zone, 'time' => time }
     end
 
     # Returns a string of the object's date and time in the format used by
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index 2b59c7a33d..2699a064d7 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -428,6 +428,15 @@ module ActiveSupport
       tzinfo.periods_for_local(time)
     end
 
+    def init_with(coder) #:nodoc:
+      initialize(coder['name'])
+    end
+
+    def encode_with(coder) #:nodoc:
+      coder.tag ="!ruby/object:#{self.class}"
+      coder.map = { 'name' => tzinfo.name }
+    end
+
     private
       def parts_to_time(parts, now)
         return if parts.empty?
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 92c233d567..79d78c02cd 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -1,6 +1,7 @@
 require 'abstract_unit'
 require 'active_support/time'
 require 'time_zone_test_helpers'
+require 'active_support/core_ext/string/strip'
 
 class TimeWithZoneTest < ActiveSupport::TestCase
   include TimeZoneTestHelpers
@@ -123,11 +124,53 @@ class TimeWithZoneTest < ActiveSupport::TestCase
   end
 
   def test_to_yaml
-    assert_match(/^--- 2000-01-01 00:00:00(\.0+)?\s*Z\n/, @twz.to_yaml)
+    yaml = <<-EOF.strip_heredoc
+      --- !ruby/object:ActiveSupport::TimeWithZone
+      utc: 2000-01-01 00:00:00.000000000 Z
+      zone: !ruby/object:ActiveSupport::TimeZone
+        name: America/New_York
+      time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(yaml, @twz.to_yaml)
   end
 
   def test_ruby_to_yaml
-    assert_match(/---\s*\n:twz: 2000-01-01 00:00:00(\.0+)?\s*Z\n/, {:twz => @twz}.to_yaml)
+    yaml = <<-EOF.strip_heredoc
+      ---
+      twz: !ruby/object:ActiveSupport::TimeWithZone
+        utc: 2000-01-01 00:00:00.000000000 Z
+        zone: !ruby/object:ActiveSupport::TimeZone
+          name: America/New_York
+        time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(yaml, { 'twz' => @twz }.to_yaml)
+  end
+
+  def test_yaml_load
+    yaml = <<-EOF.strip_heredoc
+      --- !ruby/object:ActiveSupport::TimeWithZone
+      utc: 2000-01-01 00:00:00.000000000 Z
+      zone: !ruby/object:ActiveSupport::TimeZone
+        name: America/New_York
+      time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal(@twz, YAML.load(yaml))
+  end
+
+  def test_ruby_yaml_load
+    yaml = <<-EOF.strip_heredoc
+      ---
+      twz: !ruby/object:ActiveSupport::TimeWithZone
+        utc: 2000-01-01 00:00:00.000000000 Z
+        zone: !ruby/object:ActiveSupport::TimeZone
+          name: America/New_York
+        time: 1999-12-31 19:00:00.000000000 Z
+    EOF
+
+    assert_equal({ 'twz' => @twz }, YAML.load(yaml))
   end
 
   def test_httpdate
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index ea90caa143..5e0474f449 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -487,4 +487,13 @@ class TimeZoneTest < ActiveSupport::TestCase
     assert ActiveSupport::TimeZone.us_zones.include?(ActiveSupport::TimeZone["Hawaii"])
     assert !ActiveSupport::TimeZone.us_zones.include?(ActiveSupport::TimeZone["Kuala Lumpur"])
   end
+
+  def test_to_yaml
+    assert_equal("--- !ruby/object:ActiveSupport::TimeZone\nname: Pacific/Honolulu\n", ActiveSupport::TimeZone["Hawaii"].to_yaml)
+    assert_equal("--- !ruby/object:ActiveSupport::TimeZone\nname: Europe/London\n", ActiveSupport::TimeZone["Europe/London"].to_yaml)
+  end
+
+  def test_yaml_load
+    assert_equal(ActiveSupport::TimeZone["Pacific/Honolulu"], YAML.load("--- !ruby/object:ActiveSupport::TimeZone\nname: Pacific/Honolulu\n"))
+  end
 end