diff --git a/README.markdown b/README.markdown
index d345947a1..f95d37d8d 100644
--- a/README.markdown
+++ b/README.markdown
@@ -623,7 +623,7 @@ Returns a new string where runs of the same character that occur in this set are
 
 #### `str2bool`
 
-Converts a string to a boolean. This attempts to convert strings that contain values such as '1', 't', 'y', and 'yes' to 'true' and strings that contain values such as '0', 'f', 'n', and 'no' to 'false'. *Type*: rvalue.
+Converts a string to a boolean regardless of case. This attempts to convert strings that contain values such as '1', 't', 'y', 'Y', 'YES','yes', and 'TRUE' to 'true' and strings that contain values such as '0', 'f','F', 'N','n', 'NO','FALSE', and 'no' to 'false'. *Type*: rvalue.  
 
 #### `str2saltedsha512`
 
diff --git a/lib/puppet/parser/functions/str2bool.rb b/lib/puppet/parser/functions/str2bool.rb
index 446732ece..8def131e3 100644
--- a/lib/puppet/parser/functions/str2bool.rb
+++ b/lib/puppet/parser/functions/str2bool.rb
@@ -5,8 +5,8 @@
 module Puppet::Parser::Functions
   newfunction(:str2bool, :type => :rvalue, :doc => <<-EOS
 This converts a string to a boolean. This attempt to convert strings that
-contain things like: y, 1, t, true to 'true' and strings that contain things
-like: 0, f, n, false, no to 'false'.
+contain things like: Y,y, 1, T,t, TRUE,true to 'true' and strings that contain things
+like: 0, F,f, N,n, false, FALSE, no to 'false'.
     EOS
   ) do |arguments|
 
@@ -32,8 +32,8 @@ module Puppet::Parser::Functions
       # We yield false in this case.
       #
       when /^$/, '' then false # Empty string will be false ...
-      when /^(1|t|y|true|yes)$/  then true
-      when /^(0|f|n|false|no)$/  then false
+      when /^(1|t|y|true|yes)$/i  then true
+      when /^(0|f|n|false|no)$/i  then false
       when /^(undef|undefined)$/ then false # This is not likely to happen ...
       else
         raise(Puppet::ParseError, 'str2bool(): Unknown type of boolean given')
diff --git a/spec/functions/str2bool_spec.rb b/spec/functions/str2bool_spec.rb
index 3b439b249..7d8c47c19 100755
--- a/spec/functions/str2bool_spec.rb
+++ b/spec/functions/str2bool_spec.rb
@@ -10,13 +10,13 @@
   it { is_expected.to run.with_params('one').and_raise_error(Puppet::ParseError, /Unknown type of boolean given/) }
 
   describe 'when testing values that mean "true"' do
-    [ '1', 't', 'y', 'true', 'yes', true ].each do |value|
+    [ 'TRUE','1', 't', 'y', 'true', 'yes', true ].each do |value|
       it { is_expected.to run.with_params(value).and_return(true) }
     end
   end
 
   describe 'when testing values that mean "false"' do
-    [ '', '0', 'f', 'n', 'false', 'no', false, 'undef', 'undefined' ].each do |value|
+    [ 'FALSE','', '0', 'f', 'n', 'false', 'no', false, 'undef', 'undefined' ].each do |value|
       it { is_expected.to run.with_params(value).and_return(false) }
     end
   end