diff --git a/kotlin-native/backend.native/tests/stdlib_external/utils.kt b/kotlin-native/backend.native/tests/stdlib_external/utils.kt
index cebad086d7e..1eb6826d3c1 100644
--- a/kotlin-native/backend.native/tests/stdlib_external/utils.kt
+++ b/kotlin-native/backend.native/tests/stdlib_external/utils.kt
@@ -44,4 +44,5 @@ public actual object BackReferenceHandling {
     actual val enclosingGroup: HandlingOption = HandlingOption.MATCH_NOTHING
     actual val nonExistentGroup: HandlingOption = HandlingOption.THROW
     actual val nonExistentNamedGroup: HandlingOption = HandlingOption.THROW
+    actual val groupZero: HandlingOption = HandlingOption.THROW
 }
\ No newline at end of file
diff --git a/libraries/stdlib/common/test/testUtils.kt b/libraries/stdlib/common/test/testUtils.kt
index 7acc2608c26..856eb4769ea 100644
--- a/libraries/stdlib/common/test/testUtils.kt
+++ b/libraries/stdlib/common/test/testUtils.kt
@@ -36,4 +36,5 @@ public expect object BackReferenceHandling {
     val enclosingGroup: HandlingOption
     val nonExistentGroup: HandlingOption
     val nonExistentNamedGroup: HandlingOption
+    val groupZero: HandlingOption
 }
\ No newline at end of file
diff --git a/libraries/stdlib/js/test/core/testUtils.kt b/libraries/stdlib/js/test/core/testUtils.kt
index 0791b9aa6ae..e53b7fe6a79 100644
--- a/libraries/stdlib/js/test/core/testUtils.kt
+++ b/libraries/stdlib/js/test/core/testUtils.kt
@@ -41,4 +41,5 @@ public actual object BackReferenceHandling {
     actual val enclosingGroup: HandlingOption = HandlingOption.IGNORE_BACK_REFERENCE_EXPRESSION
     actual val nonExistentGroup: HandlingOption = HandlingOption.THROW
     actual val nonExistentNamedGroup: HandlingOption = HandlingOption.THROW
+    actual val groupZero: HandlingOption = HandlingOption.MATCH_NOTHING
 }
\ No newline at end of file
diff --git a/libraries/stdlib/jvm/test/testUtilsJVM.kt b/libraries/stdlib/jvm/test/testUtilsJVM.kt
index 4e6a6fbf77c..43e1fe1c148 100644
--- a/libraries/stdlib/jvm/test/testUtilsJVM.kt
+++ b/libraries/stdlib/jvm/test/testUtilsJVM.kt
@@ -55,4 +55,5 @@ public actual object BackReferenceHandling {
     actual val enclosingGroup: HandlingOption = HandlingOption.MATCH_NOTHING
     actual val nonExistentGroup: HandlingOption = HandlingOption.MATCH_NOTHING
     actual val nonExistentNamedGroup: HandlingOption = HandlingOption.THROW
+    actual val groupZero: HandlingOption = HandlingOption.THROW
 }
\ No newline at end of file
diff --git a/libraries/stdlib/test/text/RegexTest.kt b/libraries/stdlib/test/text/RegexTest.kt
index d2ca64dc57c..d91a6f4fa93 100644
--- a/libraries/stdlib/test/text/RegexTest.kt
+++ b/libraries/stdlib/test/text/RegexTest.kt
@@ -241,6 +241,9 @@ class RegexTest {
         testInvalidBackReference(BackReferenceHandling.nonExistentGroup, pattern = "a(a)\\2")
         testInvalidBackReference(BackReferenceHandling.enclosingGroup, pattern = "a(a\\1)")
         testInvalidBackReference(BackReferenceHandling.notYetDefinedGroup, pattern = "a\\1(a)")
+
+        testInvalidBackReference(BackReferenceHandling.groupZero, pattern = "aa\\0")
+        testInvalidBackReference(BackReferenceHandling.groupZero, pattern = "a\\0a")
     }
 
     @Test fun matchCharWithOctalValue() {
@@ -306,7 +309,7 @@ class RegexTest {
 
     // TODO: Test comment mode enabled and group name is separated by space, (before, in the middle, after)
     // TODO: Test comment mode enabled and back reference group index is separated by space, (before, in the middle, after)
-    // TODO: Test back reference with \0
+    // TODO: IllegalArgumentException to java.util.regex.PatternSyntaxException where possible
 
     @Test fun matchMultiline() {
         val regex = "^[a-z]*$".toRegex(setOf(RegexOption.IGNORE_CASE, RegexOption.MULTILINE))
diff --git a/libraries/stdlib/wasm/test/testUtils.kt b/libraries/stdlib/wasm/test/testUtils.kt
index 7d02483e5de..ef5c81dbc7f 100644
--- a/libraries/stdlib/wasm/test/testUtils.kt
+++ b/libraries/stdlib/wasm/test/testUtils.kt
@@ -42,4 +42,5 @@ public actual object BackReferenceHandling {
     actual val enclosingGroup: HandlingOption = HandlingOption.MATCH_NOTHING
     actual val nonExistentGroup: HandlingOption = HandlingOption.THROW
     actual val nonExistentNamedGroup: HandlingOption = HandlingOption.THROW
+    actual val groupZero: HandlingOption = HandlingOption.THROW
 }
\ No newline at end of file