diff --git a/drivers/usbhost/hid_parser.c b/drivers/usbhost/hid_parser.c
index fa4160372f..d1c4b6d405 100644
--- a/drivers/usbhost/hid_parser.c
+++ b/drivers/usbhost/hid_parser.c
@@ -37,6 +37,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <debug.h>
+#include <string.h>
 
 #include <nuttx/usb/hid.h>
 #include <nuttx/usb/hid_parser.h>
diff --git a/include/dsp.h b/include/dsp.h
index fa30f9176f..923dbceada 100644
--- a/include/dsp.h
+++ b/include/dsp.h
@@ -29,12 +29,9 @@
 
 #include <stddef.h>
 #include <stdint.h>
-#include <string.h>
 #include <stdbool.h>
 #include <math.h>
 
-#include <assert.h>
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
diff --git a/include/dspb16.h b/include/dspb16.h
index 258de025ee..3d0f292a5d 100644
--- a/include/dspb16.h
+++ b/include/dspb16.h
@@ -29,12 +29,9 @@
 
 #include <stddef.h>
 #include <stdint.h>
-#include <string.h>
 #include <stdbool.h>
 #include <fixedmath.h>
 
-#include <assert.h>
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
diff --git a/include/nuttx/net/bluetooth.h b/include/nuttx/net/bluetooth.h
index cd9d422c3e..e208d76cd3 100644
--- a/include/nuttx/net/bluetooth.h
+++ b/include/nuttx/net/bluetooth.h
@@ -26,7 +26,6 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
-#include <string.h>
 #include <nuttx/wireless/bluetooth/bt_hci.h>
 
 /****************************************************************************
diff --git a/include/nuttx/rptun/rptun.h b/include/nuttx/rptun/rptun.h
index c875643c6f..cb4f99126c 100644
--- a/include/nuttx/rptun/rptun.h
+++ b/include/nuttx/rptun/rptun.h
@@ -32,8 +32,6 @@
 #include <nuttx/fs/ioctl.h>
 #include <openamp/open_amp.h>
 
-#include <string.h>
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
diff --git a/include/nuttx/usb/hid_parser.h b/include/nuttx/usb/hid_parser.h
index 9d795bec1e..d71ebab3f5 100644
--- a/include/nuttx/usb/hid_parser.h
+++ b/include/nuttx/usb/hid_parser.h
@@ -25,7 +25,6 @@
  * Included Files
  ****************************************************************************/
 
-#include <string.h>
 #include <stdbool.h>
 
 /****************************************************************************
diff --git a/libs/libdsp/lib_motor.c b/libs/libdsp/lib_motor.c
index c65f23890a..dfc477d99e 100644
--- a/libs/libdsp/lib_motor.c
+++ b/libs/libdsp/lib_motor.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <dsp.h>
+#include <string.h>
 
 /****************************************************************************
  * Pre-processor Definitions
diff --git a/libs/libdsp/lib_motor_b16.c b/libs/libdsp/lib_motor_b16.c
index fca3ff08e0..1f466de76a 100644
--- a/libs/libdsp/lib_motor_b16.c
+++ b/libs/libdsp/lib_motor_b16.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <dspb16.h>
+#include <string.h>
 
 /****************************************************************************
  * Pre-processor Definitions
diff --git a/libs/libdsp/lib_observer.c b/libs/libdsp/lib_observer.c
index 8d8c11def3..8e0546277b 100644
--- a/libs/libdsp/lib_observer.c
+++ b/libs/libdsp/lib_observer.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <dsp.h>
+#include <string.h>
 
 /****************************************************************************
  * Pre-processor Definitions
diff --git a/libs/libdsp/lib_pid.c b/libs/libdsp/lib_pid.c
index b0e9ea735d..d39f7fe624 100644
--- a/libs/libdsp/lib_pid.c
+++ b/libs/libdsp/lib_pid.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <dsp.h>
+#include <string.h>
 
 /****************************************************************************
  * Public Functions
diff --git a/libs/libdsp/lib_pid_b16.c b/libs/libdsp/lib_pid_b16.c
index ec68e14d19..b534c540e0 100644
--- a/libs/libdsp/lib_pid_b16.c
+++ b/libs/libdsp/lib_pid_b16.c
@@ -23,6 +23,7 @@
  ****************************************************************************/
 
 #include <dspb16.h>
+#include <string.h>
 
 /****************************************************************************
  * Public Functions
diff --git a/libs/libdsp/lib_pmsm_model.c b/libs/libdsp/lib_pmsm_model.c
index 839e79900f..cc7f6588b2 100644
--- a/libs/libdsp/lib_pmsm_model.c
+++ b/libs/libdsp/lib_pmsm_model.c
@@ -113,6 +113,7 @@
 
 #include <assert.h>
 #include <dsp.h>
+#include <string.h>
 
 /****************************************************************************
  * Public Functions
diff --git a/libs/libdsp/lib_pmsm_model_b16.c b/libs/libdsp/lib_pmsm_model_b16.c
index 2ef4ec5e5f..c85beb7f02 100644
--- a/libs/libdsp/lib_pmsm_model_b16.c
+++ b/libs/libdsp/lib_pmsm_model_b16.c
@@ -26,6 +26,7 @@
 
 #include <assert.h>
 #include <dspb16.h>
+#include <string.h>
 
 /****************************************************************************
  * Public Functions
diff --git a/libs/libdsp/lib_svm.c b/libs/libdsp/lib_svm.c
index 8fdad982cd..03546bff6f 100644
--- a/libs/libdsp/lib_svm.c
+++ b/libs/libdsp/lib_svm.c
@@ -23,8 +23,8 @@
  ****************************************************************************/
 
 #include <assert.h>
-
 #include <dsp.h>
+#include <string.h>
 
 /****************************************************************************
  * Private Functions
diff --git a/libs/libdsp/lib_svm_b16.c b/libs/libdsp/lib_svm_b16.c
index fc660c9b38..7f26717b1c 100644
--- a/libs/libdsp/lib_svm_b16.c
+++ b/libs/libdsp/lib_svm_b16.c
@@ -23,8 +23,8 @@
  ****************************************************************************/
 
 #include <assert.h>
-
 #include <dspb16.h>
+#include <string.h>
 
 /****************************************************************************
  * Private Functions