diff --git a/activesupport/CHANGELOG b/activesupport/CHANGELOG
index 468285ec43..d1ad138f50 100644
--- a/activesupport/CHANGELOG
+++ b/activesupport/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add String#squish and String#squish! to remove consecutive chunks of whitespace.  #11123 [jordi, Henrik N]
+
 * Serialize BigDecimals as Floats when using to_yaml. #8746 [ernesto.jimenez]
 
 * Adding TimeWithZone #to_yaml, #to_datetime, #eql? and method aliases for duck-typing compatibility with Time [Geoff Buesing]
diff --git a/activesupport/lib/active_support/core_ext/string.rb b/activesupport/lib/active_support/core_ext/string.rb
index 5497b6f6f6..a83474f278 100644
--- a/activesupport/lib/active_support/core_ext/string.rb
+++ b/activesupport/lib/active_support/core_ext/string.rb
@@ -5,10 +5,12 @@ require 'active_support/core_ext/string/starts_ends_with'
 require 'active_support/core_ext/string/iterators' unless 'test'.respond_to?(:each_char)
 require 'active_support/core_ext/string/unicode'
 require 'active_support/core_ext/string/xchar'
+require 'active_support/core_ext/string/filters'
 
 class String #:nodoc:
   include ActiveSupport::CoreExtensions::String::Access
   include ActiveSupport::CoreExtensions::String::Conversions
+  include ActiveSupport::CoreExtensions::String::Filters
   include ActiveSupport::CoreExtensions::String::Inflections
   if RUBY_VERSION < '1.9'
     include ActiveSupport::CoreExtensions::String::StartsEndsWith
diff --git a/activesupport/lib/active_support/core_ext/string/filters.rb b/activesupport/lib/active_support/core_ext/string/filters.rb
new file mode 100644
index 0000000000..3a69131ea0
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/string/filters.rb
@@ -0,0 +1,24 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module String #:nodoc:
+      module Filters
+        # Returns the string, first removing all whitespace on both ends of
+        # the string, and then changing remaining consecutive whitespace
+        # groups into one space each.
+        #
+        # Examples:
+        #   %{ Multi-line
+        #      string }.squish                   # => "Multi-line string"
+        #   " foo   bar    \n   \t   boo".squish # => "foo bar boo"
+        def squish
+          strip.gsub(/\s+/, ' ')
+        end
+
+        # Performs a destructive squish. See String#squish.
+        def squish!
+          replace(squish)
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index e1525d6170..19a30f1730 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -168,6 +168,23 @@ class StringInflectionsTest < Test::Unit::TestCase
     assert !s.end_with?('el')
   end
 
+  def test_string_squish
+    original = %{ A string with tabs(\t\t), newlines(\n\n), and
+                  many spaces(  ). }
+
+    expected = "A string with tabs( ), newlines( ), and many spaces( )."
+
+    # Make sure squish returns what we expect:
+    assert_equal original.squish,  expected
+    # But doesn't modify the original string:
+    assert_not_equal original, expected
+
+    # Make sure squish! returns what we expect:
+    assert_equal original.squish!, expected
+    # And changes the original string:
+    assert_equal original, expected
+  end
+
   if RUBY_VERSION < '1.9'
     def test_each_char_with_utf8_string_when_kcode_is_utf8
       old_kcode, $KCODE = $KCODE, 'UTF8'