diff --git a/lib/puppet/type/mysql_grant.rb b/lib/puppet/type/mysql_grant.rb
index 8262e1e53..d6e354345 100644
--- a/lib/puppet/type/mysql_grant.rb
+++ b/lib/puppet/type/mysql_grant.rb
@@ -60,13 +60,24 @@ def initialize(*args)
   newproperty(:user) do
     desc 'User to operate on.'
     validate do |value|
-      # https://dev.mysql.com/doc/refman/5.1/en/account-names.html
-      # Regex should problably be more like this: /^[`'"]?[^`'"]*[`'"]?@[`'"]?[\w%\.]+[`'"]?$/
-      raise(ArgumentError, "Invalid user #{value}") unless value =~ /[\w-]*@[\w%\.:]+/
-      username = value.split('@')[0]
-      if username.size > 16
-        raise ArgumentError, 'MySQL usernames are limited to a maximum of 16 characters'
+      # http://dev.mysql.com/doc/refman/5.5/en/identifiers.html
+      # If at least one special char is used, string must be quoted
+
+      # http://stackoverflow.com/questions/8055727/negating-a-backreference-in-regular-expressions/8057827#8057827
+      if matches = /^(['`"])((?!\1).)+\1@([\w%\.:]+)$/.match(value)
+        user_part = matches[2]
+        host_part = matches[3]
+      elsif matches = /^([0-9a-zA-Z$_]+)@([\w%\.:]+)$/.match(value)
+        user_part = matches[1]
+        host_part = matches[2]
+      elsif matches = /^(?:(?!['`"]).*)([^0-9a-zA-Z$_]).*@.+$/.match(value)
+        # does not start with a quote, but contains a special character
+        raise(ArgumentError, "Database user #{value} must be properly quoted, invalid character: '#{matches[1]}'")
+      else
+        raise(ArgumentError, "Invalid database user #{value}")
       end
+
+      raise(ArgumentError, 'MySQL usernames are limited to a maximum of 16 characters') unless user_part.size <= 16
     end
   end
 
diff --git a/lib/puppet/type/mysql_user.rb b/lib/puppet/type/mysql_user.rb
index 5078649de..271baac24 100644
--- a/lib/puppet/type/mysql_user.rb
+++ b/lib/puppet/type/mysql_user.rb
@@ -10,19 +10,28 @@
     desc "The name of the user. This uses the 'username@hostname' or username@hostname."
     validate do |value|
       # http://dev.mysql.com/doc/refman/5.5/en/identifiers.html
-      # Regex should problably be more like this: /^[`'"]?[^`'"]*[`'"]?@[`'"]?[\w%\.]+[`'"]?$/
       # If at least one special char is used, string must be quoted
-      raise(ArgumentError, "Database user #{value} must be quotted as it contains special characters") if value =~ /^[^'`"].*[^0-9a-zA-Z$_].*[^'`"]@[\w%\.:]+/
-      raise(ArgumentError, "Invalid database user #{value}") unless value =~ /^(?:['`"][^'`"]*['`"]|[0-9a-zA-Z$_]*)@[\w%\.:]+/
-      username = value.split('@')[0]
-      if not ((username =~ /['"`]*['"`]$/ and username.size <= 18) or username.size <= 16)
-        raise ArgumentError, 'MySQL usernames are limited to a maximum of 16 characters'
+
+      # http://stackoverflow.com/questions/8055727/negating-a-backreference-in-regular-expressions/8057827#8057827
+      if matches = /^(['`"])((?:(?!\1).)+)\1@([\w%\.:]+)$/.match(value)
+        user_part = matches[2]
+        host_part = matches[3]
+      elsif matches = /^([0-9a-zA-Z$_]+)@([\w%\.:]+)$/.match(value)
+        user_part = matches[1]
+        host_part = matches[2]
+      elsif matches = /^(?:(?!['`"]).*)([^0-9a-zA-Z$_]).*@.+$/.match(value)
+        # does not start with a quote, but contains a special character
+        raise(ArgumentError, "Database user #{value} must be properly quoted, invalid character: '#{matches[1]}'")
+      else
+        raise(ArgumentError, "Invalid database user #{value}")
       end
+
+      raise(ArgumentError, 'MySQL usernames are limited to a maximum of 16 characters') if user_part.size > 16
     end
 
     munge do |value|
-      user_part, host_part = value.split('@')
-      "#{user_part}@#{host_part.downcase}"
+      matches = /^((['`"]?).+\2)@([\w%\.:]+)$/.match(value)
+      "#{matches[1]}@#{matches[3].downcase}"
     end
   end
 
diff --git a/spec/unit/puppet/type/mysql_user_spec.rb b/spec/unit/puppet/type/mysql_user_spec.rb
index 86d56d7cd..52439f468 100644
--- a/spec/unit/puppet/type/mysql_user_spec.rb
+++ b/spec/unit/puppet/type/mysql_user_spec.rb
@@ -81,7 +81,15 @@
     it 'should fail with an unquotted username with special char' do
       expect {
         Puppet::Type.type(:mysql_user).new(:name => 'in-valid@localhost', :password_hash => 'pass')
-      }.to raise_error /Database user in-valid@localhost must be quotted/
+      }.to raise_error /Database user in-valid@localhost must be properly quoted, invalid character: '-'/
+    end
+  end
+
+  context 'using "misquoted@localhost' do
+    it 'should fail with a misquoted username is used' do
+      expect {
+        Puppet::Type.type(:mysql_user).new(:name => '"misquoted@localhost', :password_hash => 'pass')
+      }.to raise_error /Invalid database user "misquoted@localhost/
     end
   end
 end