diff --git a/include/openthread/cli.h b/include/openthread/cli.h
index 84606c2b5..e2b6f8b36 100644
--- a/include/openthread/cli.h
+++ b/include/openthread/cli.h
@@ -140,9 +140,9 @@ void otCliUartAppendResult(otError aError);
  * @param[in]  aLogLevel   The log level.
  * @param[in]  aLogRegion  The log region.
  * @param[in]  aFormat     A pointer to the format string.
- * @param[in]  ap          va_list matching aFormat.
+ * @param[in]  aArgs       va_list matching aFormat.
  */
-void otCliPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list ap);
+void otCliPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list aArgs);
 
 /**
  * @}
diff --git a/include/openthread/diag.h b/include/openthread/diag.h
index a59844dd8..844251aaf 100644
--- a/include/openthread/diag.h
+++ b/include/openthread/diag.h
@@ -62,13 +62,13 @@ void otDiagInit(otInstance *aInstance);
 /**
  * This function processes a factory diagnostics command line.
  *
- * @param[in]  argc  The argument counter of diagnostics command line.
- * @param[in]  argv  The argument vector of diagnostics command line.
+ * @param[in]  aArgc  The argument counter of diagnostics command line.
+ * @param[in]  aArgv  The argument vector of diagnostics command line.
  *
  * @returns A pointer to the output string.
  *
  */
-char *otDiagProcessCmd(int argc, char *argv[]);
+char *otDiagProcessCmd(int aArgc, char *aArgv[]);
 
 /**
  * This function processes a factory diagnostics command line.
diff --git a/include/openthread/icmp6.h b/include/openthread/icmp6.h
index aed42dfc9..2d26d4ed0 100644
--- a/include/openthread/icmp6.h
+++ b/include/openthread/icmp6.h
@@ -166,8 +166,8 @@ otError otIcmp6RegisterHandler(otInstance *aInstance, otIcmp6Handler *aHandler);
  *                           May be zero.
  *
  */
-otError otIcmp6SendEchoRequest(otInstance *aInstance, otMessage *aMessage,
-                               const otMessageInfo *aMessageInfo, uint16_t aIdentifier);
+otError otIcmp6SendEchoRequest(otInstance *aInstance, otMessage *aMessage, const otMessageInfo *aMessageInfo,
+                               uint16_t aIdentifier);
 
 /**
  * @}
diff --git a/include/openthread/instance.h b/include/openthread/instance.h
index 66c4e72c5..cea69da86 100644
--- a/include/openthread/instance.h
+++ b/include/openthread/instance.h
@@ -103,7 +103,8 @@ typedef void (OTCALL *otDeviceAvailabilityChangedCallback)(bool aAdded, const GU
  *
  */
 OTAPI void OTCALL otSetDeviceAvailabilityChangedCallback(otApiInstance *aApiInstance,
-                                                         otDeviceAvailabilityChangedCallback aCallback, void *aCallbackContext);
+                                                         otDeviceAvailabilityChangedCallback aCallback,
+                                                         void *aCallbackContext);
 
 /**
  * This function querys the list of OpenThread device contexts on the system.
diff --git a/include/openthread/ip6.h b/include/openthread/ip6.h
index 4cf739e14..6d47968eb 100644
--- a/include/openthread/ip6.h
+++ b/include/openthread/ip6.h
@@ -347,13 +347,13 @@ const uint16_t *otIp6GetUnsecurePorts(otInstance *aInstance, uint8_t *aNumEntrie
 /**
  * Test if two IPv6 addresses are the same.
  *
- * @param[in]  a  A pointer to the first IPv6 address to compare.
- * @param[in]  b  A pointer to the second IPv6 address to compare.
+ * @param[in]  aFrist   A pointer to the first IPv6 address to compare.
+ * @param[in]  aSecond  A pointer to the second IPv6 address to compare.
  *
  * @retval TRUE   The two IPv6 addresses are the same.
  * @retval FALSE  The two IPv6 addresses are not the same.
  */
-OTAPI bool OTCALL otIp6IsAddressEqual(const otIp6Address *a, const otIp6Address *b);
+OTAPI bool OTCALL otIp6IsAddressEqual(const otIp6Address *aFirst, const otIp6Address *aSecond);
 
 /**
  * Convert a human-readable IPv6 address string into a binary representation.
diff --git a/include/openthread/ncp.h b/include/openthread/ncp.h
index 371a10801..bdad6d44b 100644
--- a/include/openthread/ncp.h
+++ b/include/openthread/ncp.h
@@ -208,9 +208,9 @@ void otNcpRegisterLegacyHandlers(const otNcpLegacyHandlers *aHandlers);
  * @param[in]  aLogLevel   The log level.
  * @param[in]  aLogRegion  The log region.
  * @param[in]  aFormat     A pointer to the format string.
- * @param[in]  ap          va_list matching aFormat.
+ * @param[in]  aArgs       va_list matching aFormat.
  */
-void otNcpPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list ap);
+void otNcpPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list aArgs);
 
 /**
  * @}
diff --git a/src/cli/cli_uart.cpp b/src/cli/cli_uart.cpp
index df51752dc..296c18984 100644
--- a/src/cli/cli_uart.cpp
+++ b/src/cli/cli_uart.cpp
@@ -294,14 +294,14 @@ void Uart::SendDoneTask(void)
     Send();
 }
 
-extern "C" void otCliPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list ap)
+extern "C" void otCliPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list aArgs)
 {
     if (NULL == Uart::sUartServer)
     {
         return;
     }
 
-    Uart::sUartServer->OutputFormatV(aFormat, ap);
+    Uart::sUartServer->OutputFormatV(aFormat, aArgs);
     Uart::sUartServer->OutputFormat("\r\n");
 
     OT_UNUSED_VARIABLE(aLogLevel);
diff --git a/src/core/api/ip6_api.cpp b/src/core/api/ip6_api.cpp
index 337e2451a..904384628 100644
--- a/src/core/api/ip6_api.cpp
+++ b/src/core/api/ip6_api.cpp
@@ -86,18 +86,19 @@ const otNetifAddress *otIp6GetUnicastAddresses(otInstance *aInstance)
     return instance.GetThreadNetif().GetUnicastAddresses();
 }
 
-otError otIp6AddUnicastAddress(otInstance *aInstance, const otNetifAddress *address)
+otError otIp6AddUnicastAddress(otInstance *aInstance, const otNetifAddress *aAddress)
 {
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    return instance.GetThreadNetif().AddExternalUnicastAddress(*static_cast<const Ip6::NetifUnicastAddress *>(address));
+    return instance.GetThreadNetif().AddExternalUnicastAddress(
+               *static_cast<const Ip6::NetifUnicastAddress *>(aAddress));
 }
 
-otError otIp6RemoveUnicastAddress(otInstance *aInstance, const otIp6Address *address)
+otError otIp6RemoveUnicastAddress(otInstance *aInstance, const otIp6Address *aAddress)
 {
     Instance &instance = *static_cast<Instance *>(aInstance);
 
-    return instance.GetThreadNetif().RemoveExternalUnicastAddress(*static_cast<const Ip6::Address *>(address));
+    return instance.GetThreadNetif().RemoveExternalUnicastAddress(*static_cast<const Ip6::Address *>(aAddress));
 }
 
 const otNetifMulticastAddress *otIp6GetMulticastAddresses(otInstance *aInstance)
@@ -233,14 +234,14 @@ const uint16_t *otIp6GetUnsecurePorts(otInstance *aInstance, uint8_t *aNumEntrie
     return instance.GetThreadNetif().GetIp6Filter().GetUnsecurePorts(*aNumEntries);
 }
 
-bool otIp6IsAddressEqual(const otIp6Address *a, const otIp6Address *b)
+bool otIp6IsAddressEqual(const otIp6Address *aFirst, const otIp6Address *aSecond)
 {
-    return *static_cast<const Ip6::Address *>(a) == *static_cast<const Ip6::Address *>(b);
+    return *static_cast<const Ip6::Address *>(aFirst) == *static_cast<const Ip6::Address *>(aSecond);
 }
 
-otError otIp6AddressFromString(const char *str, otIp6Address *address)
+otError otIp6AddressFromString(const char *aString, otIp6Address *aAddress)
 {
-    return static_cast<Ip6::Address *>(address)->FromString(str);
+    return static_cast<Ip6::Address *>(aAddress)->FromString(aString);
 }
 
 uint8_t otIp6PrefixMatch(const otIp6Address *aFirst, const otIp6Address *aSecond)
diff --git a/src/diag/openthread-diag.cpp b/src/diag/openthread-diag.cpp
index 2d8d9efbe..8033f2352 100644
--- a/src/diag/openthread-diag.cpp
+++ b/src/diag/openthread-diag.cpp
@@ -48,21 +48,21 @@ void otDiagInit(otInstance *aInstance)
     Diag::Init(aInstance);
 }
 
-char *otDiagProcessCmd(int argc, char *argv[])
+char *otDiagProcessCmd(int aArgc, char *aArgv[])
 {
-    return Diag::ProcessCmd(argc, argv);
+    return Diag::ProcessCmd(aArgc, aArgv);
 }
 
-char *otDiagProcessCmdLine(char *string)
+char *otDiagProcessCmdLine(char *aString)
 {
     char *argv[8];
     int argc = 0;
-    int length = static_cast<int>(strlen(string));
+    int length = static_cast<int>(strlen(aString));
     char *cmd;
 
-    for (; *string == ' '; string++, length--);
+    for (; *aString == ' '; aString++, length--);
 
-    for (cmd = string + 1; (cmd < string + length) && (cmd != NULL); ++cmd)
+    for (cmd = aString + 1; (cmd < aString + length) && (cmd != NULL); ++cmd)
     {
         if (*cmd == ' ' || *cmd == '\r' || *cmd == '\n')
         {
diff --git a/src/ncp/ncp_base.cpp b/src/ncp/ncp_base.cpp
index 1a5b00e33..036e50850 100644
--- a/src/ncp/ncp_base.cpp
+++ b/src/ncp/ncp_base.cpp
@@ -2124,12 +2124,12 @@ otError otNcpStreamWrite(int aStreamId, const uint8_t *aDataPtr, int aDataLen)
 }
 
 
-extern "C" void otNcpPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list ap)
+extern "C" void otNcpPlatLogv(otLogLevel aLogLevel, otLogRegion aLogRegion, const char *aFormat, va_list aArgs)
 {
     char logString[128];
     int charsWritten;
 
-    if ((charsWritten = vsnprintf(logString, sizeof(logString), aFormat, ap)) > 0)
+    if ((charsWritten = vsnprintf(logString, sizeof(logString), aFormat, aArgs)) > 0)
     {
         if (charsWritten > static_cast<int>(sizeof(logString) - 1))
         {