diff --git a/cscore/src/main/native/cpp/jni/CameraServerJNI.cpp b/cscore/src/main/native/cpp/jni/CameraServerJNI.cpp
index ef62f79070..536111efae 100644
--- a/cscore/src/main/native/cpp/jni/CameraServerJNI.cpp
+++ b/cscore/src/main/native/cpp/jni/CameraServerJNI.cpp
@@ -79,7 +79,7 @@ static void ListenerOnExit() {
 /// throw java exception
 static void ThrowJavaException(JNIEnv* env, const std::exception* e) {
   wpi::SmallString<128> what;
-  jclass je = 0;
+  jclass je = nullptr;
 
   if (e) {
     const char* exception_type = "std::exception";
@@ -1198,7 +1198,7 @@ Java_edu_wpi_cscore_CameraServerCvJNI_putSourceFrame
   } catch (const std::exception& e) {
     ThrowJavaException(env, &e);
   } catch (...) {
-    ThrowJavaException(env, 0);
+    ThrowJavaException(env, nullptr);
   }
 }
 
@@ -1673,7 +1673,7 @@ Java_edu_wpi_cscore_CameraServerCvJNI_grabSinkFrame
     ThrowJavaException(env, &e);
     return 0;
   } catch (...) {
-    ThrowJavaException(env, 0);
+    ThrowJavaException(env, nullptr);
     return 0;
   }
 }
@@ -1697,7 +1697,7 @@ Java_edu_wpi_cscore_CameraServerCvJNI_grabSinkFrameTimeout
     ThrowJavaException(env, &e);
     return 0;
   } catch (...) {
-    ThrowJavaException(env, 0);
+    ThrowJavaException(env, nullptr);
     return 0;
   }
 }
diff --git a/hal/src/main/native/cpp/jni/I2CJNI.cpp b/hal/src/main/native/cpp/jni/I2CJNI.cpp
index 7434906c57..b605b9550a 100644
--- a/hal/src/main/native/cpp/jni/I2CJNI.cpp
+++ b/hal/src/main/native/cpp/jni/I2CJNI.cpp
@@ -42,7 +42,7 @@ Java_edu_wpi_first_hal_I2CJNI_i2CTransaction
    jbyte sendSize, jobject dataReceived, jbyte receiveSize)
 {
   uint8_t* dataToSendPtr = nullptr;
-  if (dataToSend != 0) {
+  if (dataToSend != nullptr) {
     dataToSendPtr =
         reinterpret_cast<uint8_t*>(env->GetDirectBufferAddress(dataToSend));
   }
@@ -88,7 +88,7 @@ Java_edu_wpi_first_hal_I2CJNI_i2CWrite
 {
   uint8_t* dataToSendPtr = nullptr;
 
-  if (dataToSend != 0) {
+  if (dataToSend != nullptr) {
     dataToSendPtr =
         reinterpret_cast<uint8_t*>(env->GetDirectBufferAddress(dataToSend));
   }
diff --git a/hal/src/main/native/cpp/jni/InterruptJNI.cpp b/hal/src/main/native/cpp/jni/InterruptJNI.cpp
index 0eebdf14b7..47d37b434e 100644
--- a/hal/src/main/native/cpp/jni/InterruptJNI.cpp
+++ b/hal/src/main/native/cpp/jni/InterruptJNI.cpp
@@ -271,12 +271,12 @@ Java_edu_wpi_first_hal_InterruptJNI_attachInterruptHandler
   (JNIEnv* env, jclass, jint interruptHandle, jobject handler, jobject param)
 {
   jclass cls = env->GetObjectClass(handler);
-  if (cls == 0) {
+  if (cls == nullptr) {
     assert(false);
     return;
   }
   jmethodID mid = env->GetMethodID(cls, "apply", "(ILjava/lang/Object;)V");
-  if (mid == 0) {
+  if (mid == nullptr) {
     assert(false);
     return;
   }
diff --git a/hal/src/main/native/cpp/jni/SPIJNI.cpp b/hal/src/main/native/cpp/jni/SPIJNI.cpp
index 303c0337a6..67ef56df44 100644
--- a/hal/src/main/native/cpp/jni/SPIJNI.cpp
+++ b/hal/src/main/native/cpp/jni/SPIJNI.cpp
@@ -42,7 +42,7 @@ Java_edu_wpi_first_hal_SPIJNI_spiTransaction
    jbyte size)
 {
   uint8_t* dataToSendPtr = nullptr;
-  if (dataToSend != 0) {
+  if (dataToSend != nullptr) {
     dataToSendPtr =
         reinterpret_cast<uint8_t*>(env->GetDirectBufferAddress(dataToSend));
   }
@@ -85,7 +85,7 @@ Java_edu_wpi_first_hal_SPIJNI_spiWrite
   (JNIEnv* env, jclass, jint port, jobject dataToSend, jbyte size)
 {
   uint8_t* dataToSendPtr = nullptr;
-  if (dataToSend != 0) {
+  if (dataToSend != nullptr) {
     dataToSendPtr =
         reinterpret_cast<uint8_t*>(env->GetDirectBufferAddress(dataToSend));
   }
diff --git a/hal/src/main/native/sim/AnalogTrigger.cpp b/hal/src/main/native/sim/AnalogTrigger.cpp
index ae236bc04a..50c4ab4928 100644
--- a/hal/src/main/native/sim/AnalogTrigger.cpp
+++ b/hal/src/main/native/sim/AnalogTrigger.cpp
@@ -128,12 +128,12 @@ void HAL_SetAnalogTriggerLimitsRaw(HAL_AnalogTriggerHandle analogTriggerHandle,
 
   double trigLower =
       GetAnalogValueToVoltage(trigger->analogHandle, lower, status);
-  if (status != 0) {
+  if (status != nullptr) {
     return;
   }
   double trigUpper =
       GetAnalogValueToVoltage(trigger->analogHandle, upper, status);
-  if (status != 0) {
+  if (status != nullptr) {
     return;
   }
 
diff --git a/simulation/halsim_ws_client/src/main/native/cpp/HALSimWS.cpp b/simulation/halsim_ws_client/src/main/native/cpp/HALSimWS.cpp
index a2a077d502..da6253d589 100644
--- a/simulation/halsim_ws_client/src/main/native/cpp/HALSimWS.cpp
+++ b/simulation/halsim_ws_client/src/main/native/cpp/HALSimWS.cpp
@@ -39,14 +39,14 @@ bool HALSimWS::Initialize() {
   }
 
   const char* host = std::getenv("HALSIMWS_HOST");
-  if (host != NULL) {
+  if (host != nullptr) {
     m_host = host;
   } else {
     m_host = "localhost";
   }
 
   const char* port = std::getenv("HALSIMWS_PORT");
-  if (port != NULL) {
+  if (port != nullptr) {
     try {
       m_port = std::stoi(port);
     } catch (const std::invalid_argument& err) {
@@ -58,7 +58,7 @@ bool HALSimWS::Initialize() {
   }
 
   const char* uri = std::getenv("HALSIMWS_URI");
-  if (uri != NULL) {
+  if (uri != nullptr) {
     m_uri = uri;
   } else {
     m_uri = "/wpilibws";
diff --git a/simulation/halsim_ws_server/src/main/native/cpp/HALSimWeb.cpp b/simulation/halsim_ws_server/src/main/native/cpp/HALSimWeb.cpp
index 41420280e6..b8093a3e20 100644
--- a/simulation/halsim_ws_server/src/main/native/cpp/HALSimWeb.cpp
+++ b/simulation/halsim_ws_server/src/main/native/cpp/HALSimWeb.cpp
@@ -46,7 +46,7 @@ bool HALSimWeb::Initialize() {
   wpi::SmallString<64> tmp;
 
   const char* webroot_sys = std::getenv("HALSIMWS_SYSROOT");
-  if (webroot_sys != NULL) {
+  if (webroot_sys != nullptr) {
     wpi::StringRef tstr(webroot_sys);
     tmp.append(tstr);
   } else {
@@ -58,7 +58,7 @@ bool HALSimWeb::Initialize() {
 
   tmp.clear();
   const char* webroot_user = std::getenv("HALSIMWS_USERROOT");
-  if (webroot_user != NULL) {
+  if (webroot_user != nullptr) {
     wpi::StringRef tstr(webroot_user);
     tmp.append(tstr);
   } else {
@@ -69,14 +69,14 @@ bool HALSimWeb::Initialize() {
   m_webroot_user = wpi::Twine(tmp).str();
 
   const char* uri = std::getenv("HALSIMWS_URI");
-  if (uri != NULL) {
+  if (uri != nullptr) {
     m_uri = uri;
   } else {
     m_uri = "/wpilibws";
   }
 
   const char* port = std::getenv("HALSIMWS_PORT");
-  if (port != NULL) {
+  if (port != nullptr) {
     try {
       m_port = std::stoi(port);
     } catch (const std::invalid_argument& err) {
diff --git a/wpigui/src/main/native/include/wpigui.h b/wpigui/src/main/native/include/wpigui.h
index 2933631bfc..1c27233174 100644
--- a/wpigui/src/main/native/include/wpigui.h
+++ b/wpigui/src/main/native/include/wpigui.h
@@ -266,7 +266,7 @@ class Texture {
         m_format{oth.m_format},
         m_width{oth.m_width},
         m_height{oth.m_height} {
-    oth.m_texture = 0;
+    oth.m_texture = 0;  // NOLINT
   }
 
   Texture& operator=(const Texture&) = delete;
@@ -275,7 +275,7 @@ class Texture {
       DeleteTexture(m_texture);
     }
     m_texture = oth.m_texture;
-    oth.m_texture = 0;
+    oth.m_texture = 0;  // NOLINT
     m_format = oth.m_format;
     m_width = oth.m_width;
     m_height = oth.m_height;
diff --git a/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandRequirementsTest.cpp b/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandRequirementsTest.cpp
index 14303ceece..ad6a09b91e 100644
--- a/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandRequirementsTest.cpp
+++ b/wpilibNewCommands/src/test/native/cpp/frc2/command/CommandRequirementsTest.cpp
@@ -77,5 +77,5 @@ TEST_F(CommandRequirementsTest, DefaultCommandRequirementErrorTest) {
 
   requirement1.SetDefaultCommand(std::move(command1));
 
-  EXPECT_TRUE(requirement1.GetDefaultCommand() == NULL);
+  EXPECT_TRUE(requirement1.GetDefaultCommand() == nullptr);
 }
diff --git a/wpiutil/src/main/native/cpp/TCPStream.cpp b/wpiutil/src/main/native/cpp/TCPStream.cpp
index 1eaa3e983e..7a0ead1dac 100644
--- a/wpiutil/src/main/native/cpp/TCPStream.cpp
+++ b/wpiutil/src/main/native/cpp/TCPStream.cpp
@@ -223,7 +223,7 @@ bool TCPStream::WaitForReadEvent(int timeout) {
   tv.tv_usec = 0;
   FD_ZERO(&sdset);
   FD_SET(m_sd, &sdset);
-  if (select(m_sd + 1, &sdset, NULL, NULL, &tv) > 0) {
+  if (select(m_sd + 1, &sdset, nullptr, nullptr, &tv) > 0) {
     return true;
   }
   return false;