diff --git a/boards/msba2-common/tools/src/lpc2k_pgm.h b/boards/msba2-common/tools/src/lpc2k_pgm.h
index 0a5f5a7eeb..fef1a13e25 100644
--- a/boards/msba2-common/tools/src/lpc2k_pgm.h
+++ b/boards/msba2-common/tools/src/lpc2k_pgm.h
@@ -7,6 +7,6 @@ void change_baud(const char *baud_name);
 /* called before/after using serial device, used to have terminal
  * close the device.
 */
-void signal_terminal();
+void signal_terminal(void);
 
 #endif // LPC2K_PGM
diff --git a/cpu/native/include/native_internal.h b/cpu/native/include/native_internal.h
index cf9bf04241..67cbd46a94 100644
--- a/cpu/native/include/native_internal.h
+++ b/cpu/native/include/native_internal.h
@@ -41,13 +41,13 @@
  */
 void native_cpu_init(void);
 void native_interrupt_init(void);
-extern void native_hwtimer_pre_init();
+extern void native_hwtimer_pre_init(void);
 
-void native_irq_handler();
+void native_irq_handler(void);
 extern void _native_sig_leave_tramp(void);
 
-void _native_syscall_leave();
-void _native_syscall_enter();
+void _native_syscall_leave(void);
+void _native_syscall_enter(void);
 
 /**
  * external functions regularly wrapped in native for direct use
diff --git a/cpu/native/include/nativenet.h b/cpu/native/include/nativenet.h
index 05aa72a71b..5103c773a6 100644
--- a/cpu/native/include/nativenet.h
+++ b/cpu/native/include/nativenet.h
@@ -51,7 +51,7 @@ void nativenet_init(int transceiver_pid);
 /**
  * Shutdown transceiver
  */
-void nativenet_powerdown();
+void nativenet_powerdown(void);
 
 /**
  * Enable/disable monitor mode
@@ -82,7 +82,7 @@ radio_address_t nativenet_set_address(radio_address_t address);
  *
  * @return the address
  */
-radio_address_t nativenet_get_address();
+radio_address_t nativenet_get_address(void);
 
 /**
  * @brief Sets the IEEE long address of the nativenet transceiver.
@@ -114,7 +114,7 @@ int16_t nativenet_set_channel(uint8_t channel);
  *
  * @return the channel
  */
-int16_t nativenet_get_channel();
+int16_t nativenet_get_channel(void);
 
 /**
  * Set transceiver pan
@@ -129,11 +129,11 @@ uint16_t nativenet_set_pan(uint16_t pan);
  *
  * @return the pan
  */
-uint16_t nativenet_get_pan();
+uint16_t nativenet_get_pan(void);
 
 /**
  * Enable transceiver rx mode
  */
-void nativenet_switch_to_rx();
+void nativenet_switch_to_rx(void);
 /** @} */
 #endif /* NATIVENET_H */
diff --git a/dist/tools/linux-border_router/sixlowdriver.h b/dist/tools/linux-border_router/sixlowdriver.h
index 71e4721e9c..db9d9905d7 100644
--- a/dist/tools/linux-border_router/sixlowdriver.h
+++ b/dist/tools/linux-border_router/sixlowdriver.h
@@ -158,13 +158,13 @@ int border_add_addr(const char *ip_addr);
  *          router.
  * @return  This border router's current version.
  */
-uint16_t get_abro_version();
+uint16_t get_abro_version(void);
 
 /**
  * @brief   Increments and updates the version for ABROs send by this
  *          router.
  * @return  This border router's new ABRO version.
  */
-uint16_t get_next_abro_version();
+uint16_t get_next_abro_version(void);
 
 #endif /* SIXLOWDRIVER_H*/