diff --git a/malloc_hook.cpp b/malloc_hook.cpp
index 14fae64..7de77d1 100644
--- a/malloc_hook.cpp
+++ b/malloc_hook.cpp
@@ -13,6 +13,10 @@
 #if __unix__
 # include <sys/mman.h>
 # include <unistd.h>
+#if defined(__FreeBSD__)
+# include <pthread_np.h>
+# include <malloc_np.h>
+#endif
 # define MALLOCVIS_EXPORT
 #elif _WIN32
 # include <windows.h>
@@ -36,7 +40,9 @@
 namespace {
 
 uint32_t get_thread_id() {
-#if __unix__
+#if defined(__FreeBSD__)
+    return pthread_getthreadid_np();
+#elif __unix__
     return gettid();
 #elif _WIN32
     return GetCurrentThreadId();
@@ -213,7 +219,17 @@ struct EnableGuard {
 
 } // namespace
 
-#if __GNUC__
+#if __GNUC__ && !_WIN32
+#if defined(__FreeBSD__)
+extern "C" void* malloc(size_t size);
+extern "C" void free(void* ptr);
+extern "C" void* calloc(size_t nmemb, size_t size);
+extern "C" void* realloc(void *ptr, size_t size);
+extern "C" void * reallocarray(void *ptr, size_t nmemb,
+                                     size_t size);
+extern "C" void * valloc(size_t size);
+extern "C" void* memalign(size_t alignment, size_t size);
+#else
 extern "C" void *__libc_malloc(size_t size) noexcept;
 extern "C" void __libc_free(void *ptr) noexcept;
 extern "C" void *__libc_calloc(size_t nmemb, size_t size) noexcept;
@@ -222,7 +238,12 @@ extern "C" void *__libc_reallocarray(void *ptr, size_t nmemb,
                                      size_t size) noexcept;
 extern "C" void *__libc_valloc(size_t size) noexcept;
 extern "C" void *__libc_memalign(size_t align, size_t size) noexcept;
+#endif
+#if defined(__FreeBSD__)
+# define REAL_LIBC(name) name
+#else
 # define REAL_LIBC(name) __libc_##name
+#endif
 # ifndef MAY_OVERRIDE_MALLOC
 #  define MAY_OVERRIDE_MALLOC 1
 # endif
@@ -246,7 +267,11 @@ extern "C" void *__libc_memalign(size_t align, size_t size) noexcept;
 #  define RETURN_ADDRESS ((void *)0)
 #  pragma message("Cannot find __builtin_return_address")
 # endif
+#if defined(__FreeBSD__)
+# define CSTDLIB_NOEXCEPT
+#else
 # define CSTDLIB_NOEXCEPT noexcept
+#endif
 #elif _MSC_VER
 static void *msvc_malloc(size_t size) noexcept {
     return HeapAlloc(GetProcessHeap(), 0, size);