diff --git a/src/core/thread/key_manager.cpp b/src/core/thread/key_manager.cpp
index 6e291d9eb..f832533e9 100644
--- a/src/core/thread/key_manager.cpp
+++ b/src/core/thread/key_manager.cpp
@@ -100,7 +100,7 @@ ThreadError KeyManager::ComputeKey(uint32_t aKeySequence, uint8_t *aKey)
     return kThreadError_None;
 }
 
-uint32_t KeyManager::GetCurrentKeySequence() const
+uint32_t KeyManager::GetCurrentKeySequence(void) const
 {
     return mKeySequence;
 }
@@ -119,12 +119,12 @@ void KeyManager::SetCurrentKeySequence(uint32_t aKeySequence)
     }
 }
 
-const uint8_t *KeyManager::GetCurrentMacKey() const
+const uint8_t *KeyManager::GetCurrentMacKey(void) const
 {
     return mKey + 16;
 }
 
-const uint8_t *KeyManager::GetCurrentMleKey() const
+const uint8_t *KeyManager::GetCurrentMleKey(void) const
 {
     return mKey;
 }
@@ -141,22 +141,22 @@ const uint8_t *KeyManager::GetTemporaryMleKey(uint32_t aKeySequence)
     return mTemporaryKey;
 }
 
-uint32_t KeyManager::GetMacFrameCounter() const
+uint32_t KeyManager::GetMacFrameCounter(void) const
 {
     return mMacFrameCounter;
 }
 
-void KeyManager::IncrementMacFrameCounter()
+void KeyManager::IncrementMacFrameCounter(void)
 {
     mMacFrameCounter++;
 }
 
-uint32_t KeyManager::GetMleFrameCounter() const
+uint32_t KeyManager::GetMleFrameCounter(void) const
 {
     return mMleFrameCounter;
 }
 
-void KeyManager::IncrementMleFrameCounter()
+void KeyManager::IncrementMleFrameCounter(void)
 {
     mMleFrameCounter++;
 }
diff --git a/src/core/thread/key_manager.hpp b/src/core/thread/key_manager.hpp
index e314ddea5..901aa4e26 100644
--- a/src/core/thread/key_manager.hpp
+++ b/src/core/thread/key_manager.hpp
@@ -91,7 +91,7 @@ public:
      * @returns The current key sequence value.
      *
      */
-    uint32_t GetCurrentKeySequence() const;
+    uint32_t GetCurrentKeySequence(void) const;
 
     /**
      * This method sets the current key sequence value.
@@ -107,7 +107,7 @@ public:
      * @returns A pointer to the current MAC key.
      *
      */
-    const uint8_t *GetCurrentMacKey() const;
+    const uint8_t *GetCurrentMacKey(void) const;
 
     /**
      * This method returns a pointer to the current MLE key.
@@ -115,7 +115,7 @@ public:
      * @returns A pointer to the current MLE key.
      *
      */
-    const uint8_t *GetCurrentMleKey() const;
+    const uint8_t *GetCurrentMleKey(void) const;
 
     /**
      * This method returns a pointer to a temporary MAC key computed from the given key sequence.
@@ -143,7 +143,7 @@ public:
      * @returns The current MAC Frame Counter value.
      *
      */
-    uint32_t GetMacFrameCounter() const;
+    uint32_t GetMacFrameCounter(void) const;
 
     /**
      * This method increments the current MAC Frame Counter value.
@@ -151,7 +151,7 @@ public:
      * @returns The current MAC Frame Counter value.
      *
      */
-    void IncrementMacFrameCounter();
+    void IncrementMacFrameCounter(void);
 
     /**
      * This method returns the current MLE Frame Counter value.
@@ -159,7 +159,7 @@ public:
      * @returns The current MLE Frame Counter value.
      *
      */
-    uint32_t GetMleFrameCounter() const;
+    uint32_t GetMleFrameCounter(void) const;
 
     /**
      * This method increments the current MLE Frame Counter value.
@@ -167,7 +167,7 @@ public:
      * @returns The current MLE Frame Counter value.
      *
      */
-    void IncrementMleFrameCounter();
+    void IncrementMleFrameCounter(void);
 
 private:
     enum