diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index d39e808f5b686b0cfc0ada5c255c897fd1ad965c..33c6f429888e3a21bb28d6e8aa073c2edd73778f 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Auto-generate stable fixture UUIDs on PostgreSQL.
+
+    Fixes: #11524
+
+    *Roderick van Domburg*
+
 *   Fixed a problem where an enum would overwrite values of another enum
     with the same name in an unrelated class.
 
diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index 6f134bbef82968d74db7fb71b182071fa102bb2c..47d32fae056ce0d2ad84ede7f9de9237b966baf1 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -2,6 +2,7 @@
 require 'yaml'
 require 'zlib'
 require 'active_support/dependencies'
+require 'active_support/core_ext/securerandom'
 require 'active_record/fixture_set/file'
 require 'active_record/errors'
 
@@ -550,9 +551,13 @@ def self.create_fixtures(fixtures_directory, fixture_set_names, class_names = {}
     end
 
     # Returns a consistent, platform-independent identifier for +label+.
-    # Identifiers are positive integers less than 2^30.
-    def self.identify(label)
-      Zlib.crc32(label.to_s) % MAX_ID
+    # Integer identifiers are values less than 2^30. UUIDs are RFC 4122 version 5 SHA-1 hashes.
+    def self.identify(label, column_type = :integer)
+      if column_type == :uuid
+        SecureRandom.uuid_v5(SecureRandom::UUID_OID_NAMESPACE, label.to_s)
+      else
+        Zlib.crc32(label.to_s) % MAX_ID
+      end
     end
 
     # Superclass for the evaluation contexts used by ERB fixtures.
@@ -633,7 +638,7 @@ def table_rows
 
           # generate a primary key if necessary
           if has_primary_key_column? && !row.include?(primary_key_name)
-            row[primary_key_name] = ActiveRecord::FixtureSet.identify(label)
+            row[primary_key_name] = ActiveRecord::FixtureSet.identify(label, primary_key_type)
           end
 
           # If STI is used, find the correct subclass for association reflection
@@ -656,7 +661,8 @@ def table_rows
                   row[association.foreign_type] = $1
                 end
 
-                row[fk_name] = ActiveRecord::FixtureSet.identify(value)
+                fk_type = association.active_record.columns_hash[association.foreign_key].type
+                row[fk_name] = ActiveRecord::FixtureSet.identify(value, fk_type)
               end
             when :has_many
               if association.options[:through]
@@ -683,6 +689,10 @@ def join_table
       def name
         @association.name
       end
+
+      def primary_key_type
+        @association.klass.column_types[@association.klass.primary_key].type
+      end
     end
 
     class HasManyThroughProxy < ReflectionProxy # :nodoc:
@@ -700,17 +710,22 @@ def primary_key_name
         @primary_key_name ||= model_class && model_class.primary_key
       end
 
+      def primary_key_type
+        @primary_key_type ||= model_class && model_class.column_types[model_class.primary_key].type
+      end
+
       def add_join_records(rows, row, association)
         # This is the case when the join table has no fixtures file
         if (targets = row.delete(association.name.to_s))
-          table_name = association.join_table
-          lhs_key    = association.lhs_key
-          rhs_key    = association.rhs_key
+          table_name  = association.join_table
+          column_type = association.primary_key_type
+          lhs_key     = association.lhs_key
+          rhs_key     = association.rhs_key
 
           targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
           rows[table_name].concat targets.map { |target|
             { lhs_key => row[primary_key_name],
-              rhs_key => ActiveRecord::FixtureSet.identify(target) }
+              rhs_key => ActiveRecord::FixtureSet.identify(target, column_type) }
           }
         end
       end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index cf0235b8c52fb64516c18dd4c533a93ada22ce87..8bbc0af758263fa36f98dd00fcdbc1ffc9347f24 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -677,6 +677,12 @@ def test_cache
 class FoxyFixturesTest < ActiveRecord::TestCase
   fixtures :parrots, :parrots_pirates, :pirates, :treasures, :mateys, :ships, :computers, :developers, :"admin/accounts", :"admin/users"
 
+  if ActiveRecord::Base.connection.adapter_name == 'PostgreSQL'
+    require 'models/uuid_parent'
+    require 'models/uuid_child'
+    fixtures :uuid_parents, :uuid_children 
+  end
+
   def test_identifies_strings
     assert_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("foo"))
     assert_not_equal(ActiveRecord::FixtureSet.identify("foo"), ActiveRecord::FixtureSet.identify("FOO"))
@@ -689,6 +695,9 @@ def test_identifies_symbols
   def test_identifies_consistently
     assert_equal 207281424, ActiveRecord::FixtureSet.identify(:ruby)
     assert_equal 1066363776, ActiveRecord::FixtureSet.identify(:sapphire_2)
+
+    assert_equal 'f92b6bda-0d0d-5fe1-9124-502b18badded', ActiveRecord::FixtureSet.identify(:daddy, :uuid)
+    assert_equal 'b4b10018-ad47-595d-b42f-d8bdaa6d01bf', ActiveRecord::FixtureSet.identify(:sonny, :uuid)
   end
 
   TIMESTAMP_COLUMNS = %w(created_at created_on updated_at updated_on)
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index 5ed508a799bc94cd5ba0f6b6cd2eb572314337d5..eaf2cada9dcf59e557d95544193bab696f6b1b19 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -111,6 +111,15 @@ def verify_default_timezone_config
   end
 end
 
+def enable_uuid_ossp!(connection)
+  return false unless connection.supports_extensions?
+  return true if connection.extension_enabled?('uuid-ossp')
+
+  connection.enable_extension 'uuid-ossp'
+  connection.commit_db_transaction
+  connection.reconnect!
+end
+
 unless ENV['FIXTURE_DEBUG']
   module ActiveRecord::TestFixtures::ClassMethods
     def try_to_load_dependency_with_silence(*args)
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index 575eb34a9c9ec400e6f4a17e52f84b7a542764aa..fd0ef2f89f176597bf75bbc18c531a044297b63b 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -63,7 +63,7 @@ def test_types_line_up
       next if column_set.empty?
 
       lengths = column_set.map do |column|
-        if match = column.match(/t\.(?:integer|decimal|float|datetime|timestamp|time|date|text|binary|string|boolean)\s+"/)
+        if match = column.match(/t\.(?:integer|decimal|float|datetime|timestamp|time|date|text|binary|string|boolean|uuid)\s+"/)
           match[0].length
         end
       end
diff --git a/activerecord/test/fixtures/uuid_children.yml b/activerecord/test/fixtures/uuid_children.yml
new file mode 100644
index 0000000000000000000000000000000000000000..a7b15016e24fef4d48aae602d625de4f9bf8aedf
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_children.yml
@@ -0,0 +1,3 @@
+sonny:
+  uuid_parent: daddy
+  name: Sonny
diff --git a/activerecord/test/fixtures/uuid_parents.yml b/activerecord/test/fixtures/uuid_parents.yml
new file mode 100644
index 0000000000000000000000000000000000000000..0b40225c5cca7261a00293dbea494d2cc08ae464
--- /dev/null
+++ b/activerecord/test/fixtures/uuid_parents.yml
@@ -0,0 +1,2 @@
+daddy:
+  name: Daddy
diff --git a/activerecord/test/models/uuid_child.rb b/activerecord/test/models/uuid_child.rb
new file mode 100644
index 0000000000000000000000000000000000000000..a3d0962ad68fb9e91bde43c30ffcd34089820414
--- /dev/null
+++ b/activerecord/test/models/uuid_child.rb
@@ -0,0 +1,3 @@
+class UuidChild < ActiveRecord::Base
+  belongs_to :uuid_parent
+end
diff --git a/activerecord/test/models/uuid_parent.rb b/activerecord/test/models/uuid_parent.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5634f22d0c5ca26c65a31842df4e66b0086ed887
--- /dev/null
+++ b/activerecord/test/models/uuid_parent.rb
@@ -0,0 +1,3 @@
+class UuidParent < ActiveRecord::Base
+  has_many :uuid_children
+end
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index d9e1745029c8358ababb2722513170861d9a1dfc..da3074e90f2f34c3acfa3eae8070466ee24e21dd 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -17,6 +17,15 @@ def create_table(*args, &block)
       ActiveRecord::Base.connection.create_table(*args, &block)
       ActiveRecord::Base.connection.execute "SET GENERATOR #{args.first}_seq TO 10000"
     end
+  when "PostgreSQL"
+    enable_uuid_ossp!(ActiveRecord::Base.connection)
+    create_table :uuid_parents, id: :uuid, force: true do |t|
+      t.string :name
+    end
+    create_table :uuid_children, id: :uuid, force: true do |t|
+      t.string :name
+      t.uuid :uuid_parent_id
+    end
   end
 
 
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index ddc92dbd23a087ce11cd876e6a78014dec1b96b0..5e430d20fa6227b8fc4c7c70bc584ef50ffc0ecc 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Add `SecureRandom::uuid_v3` and `SecureRandom::uuid_v5` to support stable
+    UUID fixtures on PostgreSQL.
+
+    *Roderick van Domburg*
+
 *   Fixed `ActiveSupport::Duration#eql?` so that `1.second.eql?(1.second)` is
     true.
 
diff --git a/activesupport/lib/active_support/core_ext/securerandom.rb b/activesupport/lib/active_support/core_ext/securerandom.rb
new file mode 100644
index 0000000000000000000000000000000000000000..fec8f7c0ecfc87bb35f01b9f54eedbac0cd5c9ec
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/securerandom.rb
@@ -0,0 +1,47 @@
+module SecureRandom
+  UUID_DNS_NAMESPACE  = "k\xA7\xB8\x10\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+  UUID_URL_NAMESPACE  = "k\xA7\xB8\x11\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+  UUID_OID_NAMESPACE  = "k\xA7\xB8\x12\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+  UUID_X500_NAMESPACE = "k\xA7\xB8\x14\x9D\xAD\x11\xD1\x80\xB4\x00\xC0O\xD40\xC8" #:nodoc:
+  
+  # Generates a v5 non-random UUID (Universally Unique IDentifier).
+  #
+  # Using Digest::MD5 generates version 3 UUIDs; Digest::SHA1 generates version 5 UUIDs.
+  # ::uuid_from_hash always generates the same UUID for a given name and namespace combination.
+  #
+  # See RFC 4122 for details of UUID at: http://www.ietf.org/rfc/rfc4122.txt
+  def self.uuid_from_hash(hash_class, uuid_namespace, name)
+    if hash_class == Digest::MD5
+      version = 3
+    elsif hash_class == Digest::SHA1
+      version = 5
+    else
+      raise ArgumentError, "Expected Digest::SHA1 or Digest::MD5, got #{hash_class.name}."
+    end
+
+    hash = hash_class.new
+    hash.update(uuid_namespace)
+    hash.update(name)
+
+    ary = hash.digest.unpack('NnnnnN')
+    ary[2] = (ary[2] & 0x0FFF) | (version << 12)
+    ary[3] = (ary[3] & 0x3FFF) | 0x8000
+
+    "%08x-%04x-%04x-%04x-%04x%08x" % ary
+  end
+
+  # Convenience method for ::uuid_from_hash using Digest::MD5.
+  def self.uuid_v3(uuid_namespace, name)
+    self.uuid_from_hash(Digest::MD5, uuid_namespace, name)
+  end
+
+  # Convenience method for ::uuid_from_hash using Digest::SHA1.
+  def self.uuid_v5(uuid_namespace, name)
+    self.uuid_from_hash(Digest::SHA1, uuid_namespace, name)
+  end
+
+  class << self
+    # Alias for ::uuid.
+    alias_method :uuid_v4, :uuid
+  end
+end
diff --git a/activesupport/test/core_ext/securerandom_test.rb b/activesupport/test/core_ext/securerandom_test.rb
new file mode 100644
index 0000000000000000000000000000000000000000..71980f69108c3d53cd78583bbcf3000b07b0738e
--- /dev/null
+++ b/activesupport/test/core_ext/securerandom_test.rb
@@ -0,0 +1,28 @@
+require 'abstract_unit'
+require 'active_support/core_ext/securerandom'
+
+class SecureRandomExt < ActiveSupport::TestCase
+  def test_v3_uuids
+    assert_equal "3d813cbb-47fb-32ba-91df-831e1593ac29", SecureRandom.uuid_v3(SecureRandom::UUID_DNS_NAMESPACE, "www.widgets.com")
+    assert_equal "86df55fb-428e-3843-8583-ba3c05f290bc", SecureRandom.uuid_v3(SecureRandom::UUID_URL_NAMESPACE, "http://www.widgets.com")
+    assert_equal "8c29ab0e-a2dc-3482-b5eb-20cb2e2387a1", SecureRandom.uuid_v3(SecureRandom::UUID_OID_NAMESPACE, "1.2.3")
+    assert_equal "ee49149d-53a4-304a-890b-468229f6afc3", SecureRandom.uuid_v3(SecureRandom::UUID_X500_NAMESPACE, "cn=John Doe, ou=People, o=Acme, Inc., c=US")
+  end
+
+  def test_v5_uuids
+    assert_equal "21f7f8de-8051-5b89-8680-0195ef798b6a", SecureRandom.uuid_v5(SecureRandom::UUID_DNS_NAMESPACE, "www.widgets.com")
+    assert_equal "4e570fd8-186d-5a74-90f0-4d28e34673a1", SecureRandom.uuid_v5(SecureRandom::UUID_URL_NAMESPACE, "http://www.widgets.com")
+    assert_equal "42d5e23b-3a02-5135-85c6-52d1102f1f00", SecureRandom.uuid_v5(SecureRandom::UUID_OID_NAMESPACE, "1.2.3")
+    assert_equal "fd5b2ddf-bcfe-58b6-90d6-db50f74db527", SecureRandom.uuid_v5(SecureRandom::UUID_X500_NAMESPACE, "cn=John Doe, ou=People, o=Acme, Inc., c=US")
+  end
+
+  def test_uuid_v4_alias
+    assert_equal SecureRandom.method(:uuid_v4), SecureRandom.method(:uuid)
+  end
+
+  def test_invalid_hash_class
+    assert_raise ArgumentError do
+      SecureRandom.uuid_from_hash(Digest::SHA2, SecureRandom::UUID_OID_NAMESPACE, '1.2.3')
+    end
+  end
+end