diff --git a/core/libs/CMakeLists.txt b/core/libs/CMakeLists.txt
index ef468b08aa..35d2ccdaa3 100644
--- a/core/libs/CMakeLists.txt
+++ b/core/libs/CMakeLists.txt
@@ -327,6 +327,16 @@ if(BUILD_TESTING)
         add_subdirectory(tests/write_watch)
         add_subdirectory(tests/guest_arena)
     endif()
+    add_test_executable(guest_kernel_sys_module_internal_tests tests/GuestKernelSysModuleInternal.cpp)
+    target_include_directories(guest_kernel_sys_module_internal_tests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+    target_link_libraries(guest_kernel_sys_module_internal_tests PRIVATE libkernel_sys libkernel libc)
+    configure_windows_unwind(guest_kernel_sys_module_internal_tests)
+    add_test(NAME guest_kernel_sys_module_internal COMMAND guest_kernel_sys_module_internal_tests)
+    set_tests_properties(guest_kernel_sys_module_internal PROPERTIES TIMEOUT 20)
+    if(WIN32)
+        set_tests_properties(guest_kernel_sys_module_internal PROPERTIES ENVIRONMENT_MODIFICATION
+            "PATH=path_list_prepend:$<TARGET_FILE_DIR:libkernel_sys>")
+    endif()
     if(WIN32)
         add_test_executable(windows_write_watch_tests tests/WindowsWriteWatch.cpp)
         target_include_directories(windows_write_watch_tests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/core/libs/tests/GuestKernelSysModuleInternal.cpp b/core/libs/tests/GuestKernelSysModuleInternal.cpp
new file mode 100644
index 0000000000..0d477ebd9f
--- /dev/null
+++ b/core/libs/tests/GuestKernelSysModuleInternal.cpp
@@ -0,0 +1,88 @@
+#include "SceTypes.hpp"
+#include "prx/libkernel/KernelErrors.hpp"
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <vector>
+
+extern "C" {
+int APS5_VABI sceKernelGetModuleInfoInternal(KernelModule, ModuleInfoEx*);
+int APS5_VABI sceKernelGetModuleListInternal(KernelModule*, std::size_t, std::size_t*);
+int APS5_VABI sceKernelGetModuleList(KernelModule*, std::size_t, std::size_t*);
+int APS5_VABI sceKernelGetModuleInfo(KernelModule, ModuleInfo*);
+int APS5_VABI sceKernelGetModuleInfoFromAddr(std::uint64_t, int, ModuleInfoEx*);
+}
+
+static void Require(bool value) { if (!value) std::abort(); }
+
+static std::vector<KernelModule> List(int (APS5_VABI* list)(KernelModule*, std::size_t, std::size_t*)) {
+    std::vector<KernelModule> handles(256, -1);
+    std::size_t count = 0;
+    Require(list(handles.data(), handles.size(), &count) == 0);
+    Require(count > 0 && count < handles.size());
+    handles.resize(count);
+    return handles;
+}
+
+static void CheckList() {
+    const auto internal = List(sceKernelGetModuleListInternal);
+    Require(internal == List(sceKernelGetModuleList));
+    std::vector<KernelModule> shorter(internal.size(), -1);
+    std::size_t untouched = 99;
+    Require(sceKernelGetModuleListInternal(shorter.data(), internal.size() - 1, &untouched) == SCE_KERNEL_ERROR_ENOMEM);
+    Require(untouched == 99 && shorter.back() == -1);
+    Require(sceKernelGetModuleListInternal(nullptr, 0, &untouched) == SCE_KERNEL_ERROR_EFAULT);
+    Require(sceKernelGetModuleListInternal(shorter.data(), shorter.size(), nullptr) == SCE_KERNEL_ERROR_EFAULT);
+}
+
+static void CheckEachModule() {
+    for (const auto handle : List(sceKernelGetModuleListInternal)) {
+        ModuleInfoEx extended{};
+        extended.st_size = sizeof(ModuleInfoEx);
+        Require(sceKernelGetModuleInfoInternal(handle, &extended) == 0);
+        ModuleInfo basic{};
+        basic.st_size = sizeof(ModuleInfo);
+        Require(sceKernelGetModuleInfo(handle, &basic) == 0);
+        Require(extended.st_size == sizeof(ModuleInfoEx) && extended.id == handle);
+        Require(std::string(extended.name) == basic.name && extended.segment_count == basic.segment_count);
+        for (std::uint32_t i = 0; i < basic.segment_count; ++i)
+            Require(extended.segments[i].address == basic.segments[i].address && extended.segments[i].size == basic.segments[i].size &&
+                    extended.segments[i].prot == basic.segments[i].prot);
+    }
+}
+
+static void CheckMatchesAddressLookup() {
+    ModuleInfoEx byAddress{};
+    byAddress.st_size = sizeof(ModuleInfoEx);
+    Require(sceKernelGetModuleInfoFromAddr(reinterpret_cast<std::uintptr_t>(&sceKernelGetModuleInfo), 2, &byAddress) == 0);
+    ModuleInfoEx byHandle{};
+    byHandle.st_size = sizeof(ModuleInfoEx);
+    Require(sceKernelGetModuleInfoInternal(byAddress.id, &byHandle) == 0);
+    Require(std::memcmp(&byHandle, &byAddress, sizeof(ModuleInfoEx)) == 0);
+}
+
+static void CheckRefusals() {
+    const auto handle = List(sceKernelGetModuleListInternal).front();
+    for (const std::uint64_t size : {0x160, 0x1a4, 0x1b0, 0}) {
+        ModuleInfoEx sized{};
+        sized.st_size = size;
+        sized.name[0] = 'x';
+        Require(sceKernelGetModuleInfoInternal(handle, &sized) == SCE_KERNEL_ERROR_EINVAL);
+        Require(sized.st_size == size && sized.name[0] == 'x');
+    }
+    Require(sceKernelGetModuleInfoInternal(handle, nullptr) == SCE_KERNEL_ERROR_EFAULT);
+    ModuleInfoEx unknown{};
+    unknown.st_size = sizeof(ModuleInfoEx);
+    Require(sceKernelGetModuleInfoInternal(-1, &unknown) == SCE_KERNEL_ERROR_ESRCH && unknown.name[0] == '\0');
+}
+
+int main() {
+    CheckList();
+    CheckEachModule();
+    CheckMatchesAddressLookup();
+    CheckRefusals();
+    return 0;
+}