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;
         }
     }
 };