diff --git a/core/libs/prx/libc/CMakeLists.txt b/core/libs/prx/libc/CMakeLists.txt
index dfbe462ee1..233ff92c44 100644
--- a/core/libs/prx/libc/CMakeLists.txt
+++ b/core/libs/prx/libc/CMakeLists.txt
@@ -451,6 +451,16 @@ if(BUILD_TESTING)
         set_tests_properties(guest_libc_threads PROPERTIES ENVIRONMENT_MODIFICATION
             "PATH=path_list_prepend:$<TARGET_FILE_DIR:libc>")
     endif()
+    add_test_executable(guest_std_thread_hardware_concurrency_tests ${LIBS_INCLUDE_DIR}/tests/GuestStdThreadHardwareConcurrency.cpp)
+    target_include_directories(guest_std_thread_hardware_concurrency_tests PRIVATE ${LIBS_INCLUDE_DIR})
+    target_link_libraries(guest_std_thread_hardware_concurrency_tests PRIVATE libc)
+    configure_windows_unwind(guest_std_thread_hardware_concurrency_tests)
+    add_test(NAME guest_std_thread_hardware_concurrency COMMAND guest_std_thread_hardware_concurrency_tests)
+    set_tests_properties(guest_std_thread_hardware_concurrency PROPERTIES TIMEOUT 20)
+    if(WIN32)
+        set_tests_properties(guest_std_thread_hardware_concurrency PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libc>")
+    endif()
     add_test_executable(guest_libc_static_imports_tests ${LIBS_INCLUDE_DIR}/tests/GuestLibcStaticImports.cpp)
     target_include_directories(guest_libc_static_imports_tests PRIVATE ${LIBS_INCLUDE_DIR})
     target_link_libraries(guest_libc_static_imports_tests PRIVATE libc)
diff --git a/core/libs/prx/libc/src/Threads.cpp b/core/libs/prx/libc/src/Threads.cpp
index 1e7ea35688..4933672426 100644
--- a/core/libs/prx/libc/src/Threads.cpp
+++ b/core/libs/prx/libc/src/Threads.cpp
@@ -350,6 +350,10 @@ int SignalCondition_nid_no_patch(void** handle) {
     return threadSuccess;
 }
 
+unsigned APS5_VABI _ZNSt6thread20hardware_concurrencyEv_nid_postfix() {
+    return std::thread::hardware_concurrency();
+}
+
 int APS5_VABI _Thrd_sleep_nid_postfix(const Xtime* target, Xtime*) {
     if (!target)
         APS5_INVALID_ARG_EX;
diff --git a/core/libs/tests/GuestStdThreadHardwareConcurrency.cpp b/core/libs/tests/GuestStdThreadHardwareConcurrency.cpp
new file mode 100644
index 0000000000..6b53d172cf
--- /dev/null
+++ b/core/libs/tests/GuestStdThreadHardwareConcurrency.cpp
@@ -0,0 +1,15 @@
+#include "prx/libc/include/general/VabiMacros.hpp"
+#include <cstdio>
+#include <thread>
+
+extern "C" unsigned APS5_VABI _ZNSt6thread20hardware_concurrencyEv_nid_postfix();
+
+int main() {
+    const unsigned result = _ZNSt6thread20hardware_concurrencyEv_nid_postfix();
+    if (result != std::thread::hardware_concurrency()) {
+        std::fprintf(stderr, "guest processor hint %u differs from std::thread::hardware_concurrency %u\n",
+            result, std::thread::hardware_concurrency());
+        return 1;
+    }
+    return 0;
+}
diff --git a/docs/dev/debt/libc.md b/docs/dev/debt/libc.md
index 3fc92fea9e..abcc20d6f1 100644
--- a/docs/dev/debt/libc.md
+++ b/docs/dev/debt/libc.md
@@ -61,6 +61,7 @@
 ### Functional
 
 - [_Cosh](../../../core/libs/prx/libc/src/Math.cpp) (libc) follows the two-argument Dinkumware CRT helper used by `std::complex`, including a scaled large-finite-input path; the signature, exact result and floating-point exception behavior are not verified against the console.
+- [std::thread::hardware_concurrency](../../../core/libs/prx/libc/src/Threads.cpp) (libc, NID `CHrhwd8QSBs`) returns the host's `std::thread::hardware_concurrency()` (which may be 0 when unknown) instead of the console's processor count; no reference implements it and the value a title expects (PPSA34015 imports it) is unverified.
 - [fmodf](../../../core/libs/prx/libc/src/Math.cpp) (libc) - console `errno`, exception flags and NaN payloads remain unverified. The wrapper preserves `errno` like the existing double `fmod`, following FreeBSD 11.4 [`e_fmodf.c`](https://github.com/freebsd/freebsd-src/blob/release/11.4.0/lib/msun/src/e_fmodf.c); host `std::fmod` still supplies the result and exception flags.
 - [_FSinh and _FCosh](../../../core/libs/prx/libc/src/Math.cpp) (libc) finite results are not verified bit for bit against the console: the scaled product uses the host's binary64 hyperbolic function before rounding to binary32, rather than the float rational and `_FExp` sequence in PRAGMATA's bundled `libc.prx`. NaN preference and payloads, signed zeros, infinite operands and the range-error thresholds follow that binary's instructions; the system `libSceLibcInternal` implementation and nondefault flush-to-zero modes are unverified.