diff --git a/ext/gettext/gettext.c b/ext/gettext/gettext.c
index 05f41552c63fc..e7928795b279d 100644
--- a/ext/gettext/gettext.c
+++ b/ext/gettext/gettext.c
@@ -23,6 +23,7 @@
 #ifdef HAVE_LIBINTL
 
 #include <stdio.h>
+#include <locale.h>
 #include "ext/standard/info.h"
 #include "php_gettext.h"
 #include "gettext_arginfo.h"
@@ -61,6 +62,12 @@ ZEND_GET_MODULE(php_gettext)
 		RETURN_THROWS(); \
 	}
 
+#define PHP_DCGETTEXT_CATEGORY_CHECK(_arg_num, category) \
+	if (category == LC_ALL) { \
+		zend_argument_value_error(_arg_num, "cannot be LC_ALL"); \
+		RETURN_THROWS(); \
+	}
+
 PHP_MINFO_FUNCTION(php_gettext)
 {
 	php_info_print_table_start();
@@ -146,6 +153,7 @@ PHP_FUNCTION(dcgettext)
 
 	PHP_GETTEXT_DOMAIN_LENGTH_CHECK(1, ZSTR_LEN(domain))
 	PHP_GETTEXT_LENGTH_CHECK(2, ZSTR_LEN(msgid))
+	PHP_DCGETTEXT_CATEGORY_CHECK(3, category)
 
 	msgstr = dcgettext(ZSTR_VAL(domain), ZSTR_VAL(msgid), category);
 
@@ -260,6 +268,7 @@ PHP_FUNCTION(dcngettext)
 	PHP_GETTEXT_DOMAIN_LENGTH_CHECK(1, domain_len)
 	PHP_GETTEXT_LENGTH_CHECK(2, msgid1_len)
 	PHP_GETTEXT_LENGTH_CHECK(3, msgid2_len)
+	PHP_DCGETTEXT_CATEGORY_CHECK(5, category)
 
 	msgstr = dcngettext(domain, msgid1, msgid2, count, category);
 
diff --git a/ext/gettext/tests/dcgettext_lcall.phpt b/ext/gettext/tests/dcgettext_lcall.phpt
new file mode 100644
index 0000000000000..004ae89409eca
--- /dev/null
+++ b/ext/gettext/tests/dcgettext_lcall.phpt
@@ -0,0 +1,21 @@
+--TEST--
+dcgettext with LC_ALL is undefined behavior.
+--EXTENSIONS--
+gettext
+--FILE--
+<?php
+try {
+	dcgettext('dngettextTest', 'item', LC_ALL);
+} catch (ValueError $e) {
+	echo $e->getMessage() . PHP_EOL;
+}
+
+try {
+	dcngettext('dngettextTest', 'item', 'item2', 1, LC_ALL);
+} catch (ValueError $e) {
+	echo $e->getMessage();
+}
+?>
+--EXPECTF--
+dcgettext(): Argument #3 ($category) cannot be LC_ALL
+dcngettext(): Argument #5 ($category) cannot be LC_ALL
diff --git a/ext/gettext/tests/dcngettext.phpt b/ext/gettext/tests/dcngettext.phpt
index 715281ec8296b..2f356b1cf0c6a 100644
--- a/ext/gettext/tests/dcngettext.phpt
+++ b/ext/gettext/tests/dcngettext.phpt
@@ -11,10 +11,10 @@ if (!function_exists("dcngettext")) die("skip dcngettext() doesn't exist");
 
 var_dump(dcngettext(1,1,1,1,1));
 var_dump(dcngettext("test","test","test",1,1));
-var_dump(dcngettext("test","test","test",0,0));
+var_dump(dcngettext("test","test","test",0,1));
 var_dump(dcngettext("test","test","test",-1,-1));
 var_dump(dcngettext("","","",1,1));
-var_dump(dcngettext("","","",0,0));
+var_dump(dcngettext("","","",0,1));
 
 echo "Done\n";
 ?>