diff --git a/Ack.pm b/Ack.pm
index 9658d77b..5f0ead5b 100644
--- a/Ack.pm
+++ b/Ack.pm
@@ -341,6 +341,7 @@ File inclusion/exclusion:
   -n, --no-recurse              No descending into subdirectories
   --[no]follow                  Follow symlinks.  Default is off.
   -k, --known-types             Include only files of types that ack recognizes.
+  -K, --no-known-types          Include all files types.
 
   --type=X                      Include only X files, where X is a recognized
                                 filetype.
diff --git a/ConfigLoader.pm b/ConfigLoader.pm
index ff2adf5c..f8f34283 100644
--- a/ConfigLoader.pm
+++ b/ConfigLoader.pm
@@ -241,6 +241,10 @@ sub process_filetypes {
         push @{ $opt->{'filters'} }, @filters;
     };
 
+    $additional_specs{'K|no-known-types'} = sub {
+        @{ $opt->{'filters'} } = ();
+    };
+
     return \%additional_specs;
 }
 
diff --git a/ack b/ack
index 0c4c2bfa..d36d8968 100755
--- a/ack
+++ b/ack
@@ -1335,6 +1335,12 @@ identically to file type filters as seen in L</"Defining your own types">.
 Limit selected files to those with types that ack knows about.  This is
 equivalent to the default behavior found in ack 1.
 
+=item B<-K>, B<--no-known-types>
+
+Do not limit selected files to those with types that ack knows about.  This is
+the default behavior found in ack 2, but this allows you to override an earlier
+specification of -k or --known-types
+
 =item B<--lines=I<NUM>>
 
 Only print line I<NUM> of each file. Multiple lines can be given with multiple
diff --git a/t/ack-no-known-types.t b/t/ack-no-known-types.t
new file mode 100644
index 00000000..56f83e5c
--- /dev/null
+++ b/t/ack-no-known-types.t
@@ -0,0 +1,67 @@
+#!perl
+
+use strict;
+use warnings;
+
+use File::Find;
+use Test::More tests => 2;
+
+use lib 't';
+use Util;
+
+prep_environment();
+
+my @files = split "\n", # using qw() produces the warning "Possible attempt to put comments in qw() list"
+qq(t/swamp/0
+t/swamp/c-header.h
+t/swamp/c-source.c
+t/swamp/CMakeLists.txt
+t/swamp/crystallography-weenies.f
+t/swamp/example.R
+t/swamp/file.bar
+t/swamp/file.foo
+t/swamp/fresh.css
+t/swamp/groceries/another_subdir/fruit
+t/swamp/groceries/another_subdir/junk
+t/swamp/groceries/another_subdir/meat
+t/swamp/groceries/fruit
+t/swamp/groceries/junk
+t/swamp/groceries/meat
+t/swamp/groceries/subdir/fruit
+t/swamp/groceries/subdir/junk
+t/swamp/groceries/subdir/meat
+t/swamp/html.htm
+t/swamp/html.html
+t/swamp/incomplete-last-line.txt
+t/swamp/javascript.js
+t/swamp/lua-shebang-test
+t/swamp/Makefile
+t/swamp/Makefile.PL
+t/swamp/MasterPage.master
+t/swamp/not-an-#emacs-workfile#
+t/swamp/notaMakefile
+t/swamp/notaRakefile
+t/swamp/notes.md
+t/swamp/options-crlf.pl
+t/swamp/options.pl
+t/swamp/parrot.pir
+t/swamp/perl-test.t
+t/swamp/perl-without-extension
+t/swamp/perl.cgi
+t/swamp/perl.handler.pod
+t/swamp/perl.pl
+t/swamp/perl.pm
+t/swamp/perl.pod
+t/swamp/pipe-stress-freaks.F
+t/swamp/Rakefile
+t/swamp/Sample.ascx
+t/swamp/Sample.asmx
+t/swamp/sample.asp
+t/swamp/sample.aspx
+t/swamp/sample.rake
+t/swamp/service.svc
+t/swamp/stuff.cmake);
+
+ack_sets_match( [ '--no-known-types', '-f', 't/swamp' ], \@files, '--no-known-types test' );
+
+ack_sets_match( [ '-K', '-f', 't/swamp' ], \@files, '-K test' );