diff --git a/core/libs/prx/libc/src/Strings.cpp b/core/libs/prx/libc/src/Strings.cpp
index 27a5c5da8..2a1a52e7a 100644
--- a/core/libs/prx/libc/src/Strings.cpp
+++ b/core/libs/prx/libc/src/Strings.cpp
@@ -392,6 +392,11 @@ char16_t* APS5_VABI wcscpy_nid_postfix(char16_t* dest, const char16_t* src) {
     return dest;
 }
 
+char16_t* APS5_VABI wcscat_nid_postfix(char16_t* dest, const char16_t* src) {
+    std::memcpy(dest + Length(dest), src, (Length(src) + 1) * sizeof(char16_t));
+    return dest;
+}
+
 char16_t* APS5_VABI wcsncpy_nid_postfix(char16_t* dest, const char16_t* src, size_t n) {
     size_t index = 0;
     for (; index < n && src[index] != 0; ++index) dest[index] = src[index];
diff --git a/core/libs/tests/GuestWideStrings.cpp b/core/libs/tests/GuestWideStrings.cpp
index 64dd0afc3..9fa620aa2 100644
--- a/core/libs/tests/GuestWideStrings.cpp
+++ b/core/libs/tests/GuestWideStrings.cpp
@@ -13,6 +13,7 @@ std::size_t APS5_VABI wcslen_nid_postfix(const char16_t* s);
 int APS5_VABI wcscmp_nid_postfix(const char16_t* s1, const char16_t* s2);
 int APS5_VABI wcsncmp_nid_postfix(const char16_t* s1, const char16_t* s2, std::size_t n);
 char16_t* APS5_VABI wcscpy_nid_postfix(char16_t* dest, const char16_t* src);
+char16_t* APS5_VABI wcscat_nid_postfix(char16_t* dest, const char16_t* src);
 char16_t* APS5_VABI wcsncpy_nid_postfix(char16_t* dest, const char16_t* src, std::size_t n);
 const char16_t* APS5_VABI wcschr_nid_postfix(const char16_t* s, char16_t c);
 const char16_t* APS5_VABI wcsrchr_nid_postfix(const char16_t* s, char16_t c);
@@ -69,6 +70,14 @@ int main() {
     require(wcscpy_nid_postfix(buffer, u"wide") == buffer);
     require(same(buffer, u"wide", 5) && buffer[5] == 0xaaaa);
 
+    char16_t concatenated[8];
+    wmemset_nid_postfix(concatenated, 0xaaaa, 8);
+    concatenated[0] = 0;
+    require(wcscat_nid_postfix(concatenated, u"ab") == concatenated);
+    require(wcscat_nid_postfix(concatenated, u"世") == concatenated);
+    const char16_t expectedConcatenated[] = {u'a', u'b', u'世', 0, 0xaaaa};
+    require(same(concatenated, expectedConcatenated, 5));
+
     wmemset_nid_postfix(buffer, 0xaaaa, 8);
     require(wcsncpy_nid_postfix(buffer, u"ab", 5) == buffer);
     const char16_t padded[] = {u'a', u'b', 0, 0, 0, 0xaaaa};