diff --git a/base/HidlInternal.cpp b/base/HidlInternal.cpp
index 51f42f6..b41c0b9 100644
--- a/base/HidlInternal.cpp
+++ b/base/HidlInternal.cpp
@@ -105,7 +105,7 @@
         }
 
         struct dirent *file;
-        while ((file = readdir(dir)) != NULL) {
+        while ((file = readdir(dir)) != nullptr) {
             if (!isInstrumentationLib(file))
                 continue;
 
@@ -141,7 +141,7 @@
             }
             auto cb = (cbFun)dlsym(handle, ("HIDL_INSTRUMENTATION_FUNCTION_"
                         + package + "_" + mInterfaceName).c_str());
-            if ((error = dlerror()) != NULL) {
+            if ((error = dlerror()) != nullptr) {
                 LOG(WARNING)
                     << "couldn't find symbol: HIDL_INSTRUMENTATION_FUNCTION_"
                     << package << "_" << mInterfaceName << ", error: " << error;
diff --git a/base/Status.cpp b/base/Status.cpp
index 3b31ee6..1ba91c3 100644
--- a/base/Status.cpp
+++ b/base/Status.cpp
@@ -53,7 +53,7 @@
     }
     std::string str = std::to_string(s);
     char *err = strerror(-s);
-    if (err != NULL) {
+    if (err != nullptr) {
         str.append(1, ' ').append(err);
     }
     return str;
diff --git a/base/include/hidl/HidlSupport.h b/base/include/hidl/HidlSupport.h
index 6e37229..b878423 100644
--- a/base/include/hidl/HidlSupport.h
+++ b/base/include/hidl/HidlSupport.h
@@ -284,7 +284,7 @@
 template<typename T>
 struct hidl_vec {
     hidl_vec()
-        : mBuffer(NULL),
+        : mBuffer(nullptr),
           mSize(0),
           mOwnsBuffer(true) {
         static_assert(hidl_vec<T>::kOffsetOfBuffer == 0, "wrong offset");
@@ -342,7 +342,7 @@
         if (mOwnsBuffer) {
             delete[] mBuffer;
         }
-        mBuffer = NULL;
+        mBuffer = nullptr;
     }
 
     // Reference an existing array, optionally taking ownership. It is the
@@ -531,7 +531,7 @@
                 mBuffer[i] = data[i];
             }
         } else {
-            mBuffer = NULL;
+            mBuffer = nullptr;
         }
     }
 };
diff --git a/transport/ServiceManagement.cpp b/transport/ServiceManagement.cpp
index 4c0f0fb..3327477 100644
--- a/transport/ServiceManagement.cpp
+++ b/transport/ServiceManagement.cpp
@@ -139,7 +139,7 @@
 sp<IServiceManager1_1> defaultServiceManager1_1() {
     {
         AutoMutex _l(details::gDefaultServiceManagerLock);
-        if (details::gDefaultServiceManager != NULL) {
+        if (details::gDefaultServiceManager != nullptr) {
             return details::gDefaultServiceManager;
         }
 
@@ -151,11 +151,11 @@
 
         waitForHwServiceManager();
 
-        while (details::gDefaultServiceManager == NULL) {
+        while (details::gDefaultServiceManager == nullptr) {
             details::gDefaultServiceManager =
                     fromBinder<IServiceManager1_1, BpHwServiceManager, BnHwServiceManager>(
-                        ProcessState::self()->getContextObject(NULL));
-            if (details::gDefaultServiceManager == NULL) {
+                        ProcessState::self()->getContextObject(nullptr));
+            if (details::gDefaultServiceManager == nullptr) {
                 LOG(ERROR) << "Waited for hwservicemanager, but got nullptr.";
                 sleep(1);
             }
@@ -225,7 +225,7 @@
     if (!dir) return;
     dirent* dp;
     while ((dp = readdir(dir.get())) != nullptr) {
-        pid_t pid = strtoll(dp->d_name, NULL, 0);
+        pid_t pid = strtoll(dp->d_name, nullptr, 0);
         if (pid == 0) continue;
         std::string mapsPath = proc + dp->d_name + "/maps";
         std::ifstream ifs{mapsPath};
diff --git a/transport/token/1.0/utils/include/hidl/HybridInterface.h b/transport/token/1.0/utils/include/hidl/HybridInterface.h
index 8c3e742..984555e 100644
--- a/transport/token/1.0/utils/include/hidl/HybridInterface.h
+++ b/transport/token/1.0/utils/include/hidl/HybridInterface.h
@@ -125,13 +125,13 @@
     HalInterface* getBaseInterface() { return mBase.get(); }
     virtual status_t linkToDeath(
             const sp<IBinder::DeathRecipient>& recipient,
-            void* cookie = NULL,
+            void* cookie = nullptr,
             uint32_t flags = 0);
     virtual status_t unlinkToDeath(
             const wp<IBinder::DeathRecipient>& recipient,
-            void* cookie = NULL,
+            void* cookie = nullptr,
             uint32_t flags = 0,
-            wp<IBinder::DeathRecipient>* outRecipient = NULL);
+            wp<IBinder::DeathRecipient>* outRecipient = nullptr);
 
 protected:
     sp<HalInterface> mBase;
@@ -215,11 +215,11 @@
             const ::android::sp<::android::IBinder>& obj)               \
     {                                                                   \
         ::android::sp<I##INTERFACE> intr;                               \
-        if (obj != NULL) {                                              \
+        if (obj != nullptr) {                                           \
             intr = static_cast<I##INTERFACE*>(                          \
                 obj->queryLocalInterface(                               \
                         I##INTERFACE::descriptor).get());               \
-            if (intr == NULL) {                                         \
+            if (intr == nullptr) {                                      \
                 intr = new Hp##INTERFACE(obj);                          \
             }                                                           \
         }                                                               \
@@ -262,8 +262,8 @@
         linkToDeath(
         const sp<IBinder::DeathRecipient>& recipient,
         void* cookie, uint32_t flags) {
-    LOG_ALWAYS_FATAL_IF(recipient == NULL,
-            "linkToDeath(): recipient must be non-NULL");
+    LOG_ALWAYS_FATAL_IF(recipient == nullptr,
+            "linkToDeath(): recipient must be non-nullptr");
     {
         std::lock_guard<std::mutex> lock(mObituariesLock);
         mObituaries.push_back(new Obituary(recipient, cookie, flags, this));