diff --git a/libc/malloc_debug/malloc_debug.cpp b/libc/malloc_debug/malloc_debug.cpp
index addb5d4..014d385 100644
--- a/libc/malloc_debug/malloc_debug.cpp
+++ b/libc/malloc_debug/malloc_debug.cpp
@@ -77,6 +77,7 @@
 void* debug_realloc(void* pointer, size_t bytes);
 void* debug_calloc(size_t nmemb, size_t bytes);
 struct mallinfo debug_mallinfo();
+int debug_mallopt(int param, int value);
 int debug_posix_memalign(void** memptr, size_t alignment, size_t size);
 int debug_iterate(uintptr_t base, size_t size,
     void (*callback)(uintptr_t base, size_t size, void* arg), void* arg);
@@ -639,6 +640,10 @@
   return g_dispatch->mallinfo();
 }
 
+int debug_mallopt(int param, int value) {
+  return g_dispatch->mallopt(param, value);
+}
+
 int debug_posix_memalign(void** memptr, size_t alignment, size_t size) {
   if (DebugCallsDisabled()) {
     return g_dispatch->posix_memalign(memptr, alignment, size);
diff --git a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
index 219c21e..4fdba2e 100644
--- a/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
+++ b/libc/malloc_debug/tests/malloc_debug_unit_tests.cpp
@@ -58,6 +58,7 @@
 void debug_free_malloc_leak_info(uint8_t*);
 
 struct mallinfo debug_mallinfo();
+int debug_mallopt(int, int);
 
 #if defined(HAVE_DEPRECATED_MALLOC_FUNCS)
 void* debug_pvalloc(size_t);
@@ -128,6 +129,7 @@
   nullptr,
   nullptr,
   nullptr,
+  mallopt,
 };
 
 void VerifyAllocCalls() {
@@ -1474,6 +1476,20 @@
   ASSERT_STREQ("", getFakeLogPrint().c_str());
 }
 
+TEST_F(MallocDebugTest, debug_mallopt) {
+  Init("guard");
+
+  void* pointer = debug_malloc(150);
+  ASSERT_TRUE(pointer != nullptr);
+
+  EXPECT_EQ(0, debug_mallopt(-1000, 1));
+
+  debug_free(pointer);
+
+  ASSERT_STREQ("", getFakeLogBuf().c_str());
+  ASSERT_STREQ("", getFakeLogPrint().c_str());
+}
+
 TEST_F(MallocDebugTest, debug_posix_memalign) {
   Init("guard");