diff --git a/Tests/LibRegex/Regex.cpp b/Tests/LibRegex/Regex.cpp
index 05be810b76..76b217b98f 100644
--- a/Tests/LibRegex/Regex.cpp
+++ b/Tests/LibRegex/Regex.cpp
@@ -757,6 +757,18 @@ TEST_CASE(ECMA262_unicode_match)
         { "(?<\\ud835\\udcd1\\ud835\\udcfb\\ud835\\udcf8\\ud835\\udd00\\ud835\\udcf7>brown)"sv, "brown"sv, true, ECMAScriptFlags::Unicode },
         { "^\\s+$"sv, space_and_line_terminators },
         { "^\\s+$"sv, space_and_line_terminators, true, ECMAScriptFlags::Unicode },
+        { "[\\u0390]"sv, "\u1fd3"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\u1fd3]"sv, "\u0390"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\u0390]"sv, "\u1fd3"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
+        { "[\\u1fd3]"sv, "\u0390"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
+        { "[\\u03b0]"sv, "\u1fe3"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\u1fe3]"sv, "\u03b0"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\u03b0]"sv, "\u1fe3"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
+        { "[\\u1fe3]"sv, "\u03b0"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
+        { "[\\ufb05]"sv, "\ufb06"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\ufb06]"sv, "\ufb05"sv, false, ECMAScriptFlags::Unicode },
+        { "[\\ufb05]"sv, "\ufb06"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
+        { "[\\ufb06]"sv, "\ufb05"sv, true, combine_flags(ECMAScriptFlags::Unicode, ECMAScriptFlags::Insensitive) },
     };
 
     for (auto& test : tests) {
diff --git a/Userland/Libraries/LibRegex/RegexByteCode.cpp b/Userland/Libraries/LibRegex/RegexByteCode.cpp
index be4f609bff..c5ecf5d726 100644
--- a/Userland/Libraries/LibRegex/RegexByteCode.cpp
+++ b/Userland/Libraries/LibRegex/RegexByteCode.cpp
@@ -701,12 +701,19 @@ ALWAYS_INLINE void OpCode_Compare::compare_char(MatchInput const& input, MatchSt
         return;
 
     // FIXME: Figure out how to do this if unicode() without performing a substring split first.
-    auto input_view = input.view.unicode() ? input.view.substring_view(state.string_position, 1)[0] : input.view.code_unit_at(state.string_position_in_code_units);
+    auto input_view = input.view.unicode()
+        ? input.view.substring_view(state.string_position, 1)[0]
+        : input.view.code_unit_at(state.string_position_in_code_units);
+
     bool equal;
-    if (input.regex_options & AllFlags::Insensitive)
-        equal = to_ascii_lowercase(input_view) == to_ascii_lowercase(ch1); // FIXME: Implement case-insensitive matching for non-ascii characters
-    else
+    if (input.regex_options & AllFlags::Insensitive) {
+        if (input.view.unicode())
+            equal = Unicode::equals_ignoring_case(Utf32View { &input_view, 1 }, Utf32View { &ch1, 1 });
+        else
+            equal = to_ascii_lowercase(input_view) == to_ascii_lowercase(ch1);
+    } else {
         equal = input_view == ch1;
+    }
 
     if (equal) {
         if (inverse)