diff --git a/libc/private/KernelArgumentBlock.h b/libc/private/KernelArgumentBlock.h
index 5b6b77f..e05ceb9 100644
--- a/libc/private/KernelArgumentBlock.h
+++ b/libc/private/KernelArgumentBlock.h
@@ -42,7 +42,7 @@
     // Skip over all environment variable definitions to find the aux vector.
     // The end of the environment block is marked by a NULL pointer.
     char** p = envp;
-    while (*p != NULL) {
+    while (*p != nullptr) {
       ++p;
     }
     ++p; // Skip the NULL itself.
diff --git a/libc/private/ScopedReaddir.h b/libc/private/ScopedReaddir.h
index 3d77a40..1a59e1a 100644
--- a/libc/private/ScopedReaddir.h
+++ b/libc/private/ScopedReaddir.h
@@ -31,13 +31,13 @@
   }
 
   ~ScopedReaddir() {
-    if (dir_ != NULL) {
+    if (dir_ != nullptr) {
       closedir(dir_);
     }
   }
 
   bool IsBad() {
-    return dir_ == NULL;
+    return dir_ == nullptr;
   }
 
   dirent* ReadEntry() {
diff --git a/libc/private/bionic_futex.h b/libc/private/bionic_futex.h
index fd68007..b340690 100644
--- a/libc/private/bionic_futex.h
+++ b/libc/private/bionic_futex.h
@@ -51,11 +51,11 @@
 }
 
 static inline int __futex_wake(volatile void* ftx, int count) {
-  return __futex(ftx, FUTEX_WAKE, count, NULL, 0);
+  return __futex(ftx, FUTEX_WAKE, count, nullptr, 0);
 }
 
 static inline int __futex_wake_ex(volatile void* ftx, bool shared, int count) {
-  return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, NULL, 0);
+  return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, nullptr, 0);
 }
 
 static inline int __futex_wait(volatile void* ftx, int value, const timespec* timeout) {