diff --git a/ext/standard/basic_functions.stub.php b/ext/standard/basic_functions.stub.php
index 09f63860f1163..2fc5a0a9f3d4f 100644
--- a/ext/standard/basic_functions.stub.php
+++ b/ext/standard/basic_functions.stub.php
@@ -2439,6 +2439,11 @@ function strrchr(string $haystack, string $needle, bool $before_needle = false):
  */
 function str_contains(string $haystack, string $needle): bool {}
 
+/**
+ * @compile-time-eval
+ */
+function str_icontains(string $haystack, string $needle): bool {}
+
 /**
  * @compile-time-eval
  * @frameless-function {"arity": 2}
diff --git a/ext/standard/basic_functions_arginfo.h b/ext/standard/basic_functions_arginfo.h
index d221a221f4132..090a7d950782c 100644
--- a/ext/standard/basic_functions_arginfo.h
+++ b/ext/standard/basic_functions_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: dfd7d2cfd31312f7f6c5074c10cab54e9d1fbccc */
+ * Stub hash: fa46a068353166de787b5c53dcb1077b2a8c20c3 */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_set_time_limit, 0, 1, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, seconds, IS_LONG, 0)
@@ -918,6 +918,8 @@ ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_str_contains, 0, 2, _IS_BOOL, 0)
 	ZEND_ARG_TYPE_INFO(0, needle, IS_STRING, 0)
 ZEND_END_ARG_INFO()
 
+#define arginfo_str_icontains arginfo_str_contains
+
 #define arginfo_str_starts_with arginfo_str_contains
 
 #define arginfo_str_ends_with arginfo_str_contains
@@ -2545,6 +2547,7 @@ ZEND_FUNCTION(strrpos);
 ZEND_FUNCTION(strripos);
 ZEND_FUNCTION(strrchr);
 ZEND_FUNCTION(str_contains);
+ZEND_FUNCTION(str_icontains);
 ZEND_FUNCTION(str_starts_with);
 ZEND_FUNCTION(str_ends_with);
 ZEND_FUNCTION(chunk_split);
@@ -3146,6 +3149,7 @@ static const zend_function_entry ext_functions[] = {
 	ZEND_RAW_FENTRY("strripos", zif_strripos, arginfo_strripos, ZEND_ACC_COMPILE_TIME_EVAL, NULL, NULL)
 	ZEND_RAW_FENTRY("strrchr", zif_strrchr, arginfo_strrchr, ZEND_ACC_COMPILE_TIME_EVAL, NULL, NULL)
 	ZEND_RAW_FENTRY("str_contains", zif_str_contains, arginfo_str_contains, ZEND_ACC_COMPILE_TIME_EVAL, frameless_function_infos_str_contains, NULL)
+	ZEND_RAW_FENTRY("str_icontains", zif_str_icontains, arginfo_str_icontains, ZEND_ACC_COMPILE_TIME_EVAL, NULL, NULL)
 	ZEND_RAW_FENTRY("str_starts_with", zif_str_starts_with, arginfo_str_starts_with, ZEND_ACC_COMPILE_TIME_EVAL, frameless_function_infos_str_starts_with, NULL)
 	ZEND_RAW_FENTRY("str_ends_with", zif_str_ends_with, arginfo_str_ends_with, ZEND_ACC_COMPILE_TIME_EVAL, NULL, NULL)
 	ZEND_RAW_FENTRY("chunk_split", zif_chunk_split, arginfo_chunk_split, ZEND_ACC_COMPILE_TIME_EVAL, NULL, NULL)
diff --git a/ext/standard/string.c b/ext/standard/string.c
index f21c9be8a7bd2..7d93e978004ba 100644
--- a/ext/standard/string.c
+++ b/ext/standard/string.c
@@ -1836,6 +1836,20 @@ ZEND_FRAMELESS_FUNCTION(str_contains, 2)
 	Z_FLF_PARAM_FREE_STR(2, needle_tmp);
 }
 
+/* {{{ Checks if a string contains another, case insensitive */
+PHP_FUNCTION(str_icontains)
+{
+	zend_string *haystack, *needle;
+
+	ZEND_PARSE_PARAMETERS_START(2, 2)
+		Z_PARAM_STR(haystack)
+		Z_PARAM_STR(needle)
+	ZEND_PARSE_PARAMETERS_END();
+
+	RETURN_BOOL(php_memnistr(ZSTR_VAL(haystack), ZSTR_VAL(needle), ZSTR_LEN(needle), ZSTR_VAL(haystack) + ZSTR_LEN(haystack)));
+}
+/* }}} */
+
 /* {{{ Checks if haystack starts with needle */
 PHP_FUNCTION(str_starts_with)
 {
diff --git a/ext/standard/tests/strings/str_icontains.phpt b/ext/standard/tests/strings/str_icontains.phpt
new file mode 100644
index 0000000000000..23f2d805c3207
--- /dev/null
+++ b/ext/standard/tests/strings/str_icontains.phpt
@@ -0,0 +1,36 @@
+--TEST--
+Test str_icontains() function
+--FILE--
+<?php
+var_dump(str_icontains("test string", "test"));
+var_dump(str_icontains("test string", "string"));
+var_dump(str_icontains("test string", "strin"));
+var_dump(str_icontains("test string", "t s"));
+var_dump(str_icontains("test string", "g"));
+var_dump(str_icontains("te".chr(0)."st", chr(0)));
+var_dump(str_icontains("tEst", "test"));
+var_dump(str_icontains("teSt", "test"));
+var_dump(str_icontains("TEST", "test"));
+var_dump(str_icontains("test", "TEST"));
+var_dump(str_icontains("TESST", "TEST"));
+var_dump(str_icontains("", ""));
+var_dump(str_icontains("a", ""));
+var_dump(str_icontains("", "a"));
+var_dump(str_icontains("\\\\a", "\\a"));
+?>
+--EXPECT--
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(false)
+bool(true)
+bool(true)
+bool(false)
+bool(true)