diff --git a/examples/platforms/qpg6095/settings.cpp b/examples/platforms/qpg6095/settings.cpp
index 1cc6ba559..500e9929e 100644
--- a/examples/platforms/qpg6095/settings.cpp
+++ b/examples/platforms/qpg6095/settings.cpp
@@ -55,6 +55,11 @@ void otPlatSettingsInit(otInstance *aInstance)
     qorvoSettingsInit();
 }
 
+void otPlatSettingsDeinit(otInstance *aInstance)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+}
+
 otError otPlatSettingsGet(otInstance *aInstance, uint16_t aKey, int aIndex, uint8_t *aValue, uint16_t *aValueLength)
 {
     otError error = OT_ERROR_NOT_FOUND;
diff --git a/examples/platforms/utils/settings_flash.c b/examples/platforms/utils/settings_flash.c
index 4ea5f3b73..a8c0a2f65 100644
--- a/examples/platforms/utils/settings_flash.c
+++ b/examples/platforms/utils/settings_flash.c
@@ -303,6 +303,11 @@ void otPlatSettingsInit(otInstance *aInstance)
     }
 }
 
+void otPlatSettingsDeinit(otInstance *aInstance)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+}
+
 otError otPlatSettingsBeginChange(otInstance *aInstance)
 {
     OT_UNUSED_VARIABLE(aInstance);
diff --git a/include/openthread/platform/settings.h b/include/openthread/platform/settings.h
index 115cc67a9..d80c2aff2 100644
--- a/include/openthread/platform/settings.h
+++ b/include/openthread/platform/settings.h
@@ -60,6 +60,14 @@ extern "C" {
  */
 void otPlatSettingsInit(otInstance *aInstance);
 
+/**
+ * Performs any de-initialization for the settings subsystem, if necessary.
+ *
+ * @param[in]  aInstance The OpenThread instance structure.
+ *
+ */
+void otPlatSettingsDeinit(otInstance *aInstance);
+
 /// Fetches the value of a setting
 /** This function fetches the value of the setting identified
  *  by aKey and write it to the memory pointed to by aValue.
diff --git a/src/core/common/instance.cpp b/src/core/common/instance.cpp
index 8543da6f0..13c5282e4 100644
--- a/src/core/common/instance.cpp
+++ b/src/core/common/instance.cpp
@@ -178,6 +178,8 @@ void Instance::Finalize(void)
     IgnoreReturnValue(otThreadSetEnabled(this, false));
     IgnoreReturnValue(otIp6SetEnabled(this, false));
     IgnoreReturnValue(otLinkSetEnabled(this, false));
+
+    Get<Settings>().Deinit();
 #endif
 
 #if !OPENTHREAD_ENABLE_MULTIPLE_INSTANCES
diff --git a/src/core/common/settings.cpp b/src/core/common/settings.cpp
index 679b26937..473cdc4d7 100644
--- a/src/core/common/settings.cpp
+++ b/src/core/common/settings.cpp
@@ -97,6 +97,11 @@ void Settings::Init(void)
     otPlatSettingsInit(&GetInstance());
 }
 
+void Settings::Deinit(void)
+{
+    otPlatSettingsDeinit(&GetInstance());
+}
+
 void Settings::Wipe(void)
 {
     otPlatSettingsWipe(&GetInstance());
diff --git a/src/core/common/settings.hpp b/src/core/common/settings.hpp
index 9a481f2d9..974083b06 100644
--- a/src/core/common/settings.hpp
+++ b/src/core/common/settings.hpp
@@ -182,6 +182,14 @@ public:
      */
     void Init(void);
 
+    /**
+     * This method de-initializes the platform settings (non-volatile) module.
+     *
+     * This method should be called when OpenThread instance is no longer in use.
+     *
+     */
+    void Deinit(void);
+
     /**
      * This method removes all settings from the non-volatile store.
      *
diff --git a/src/posix/main.c b/src/posix/main.c
index 9e3232a2e..b18c14ecb 100644
--- a/src/posix/main.c
+++ b/src/posix/main.c
@@ -144,6 +144,7 @@ int main(int argc, char *argv[])
     otxConsoleDeinit();
 #endif
     otInstanceFinalize(instance);
+    otSysDeinit();
 
     return 0;
 }
diff --git a/src/posix/platform/misc.c b/src/posix/platform/misc.c
index 4ac6ded0e..1b3245294 100644
--- a/src/posix/platform/misc.c
+++ b/src/posix/platform/misc.c
@@ -45,8 +45,7 @@ static otPlatMcuPowerState gPlatMcuPowerState = OT_PLAT_MCU_POWER_STATE_ON;
 
 void otPlatReset(otInstance *aInstance)
 {
-    OT_UNUSED_VARIABLE(aInstance);
-
+    otInstanceFinalize(aInstance);
     otSysDeinit();
 
     longjmp(gResetJump, 1);
diff --git a/src/posix/platform/settings.cpp b/src/posix/platform/settings.cpp
index 283f655e0..0abba6a4b 100644
--- a/src/posix/platform/settings.cpp
+++ b/src/posix/platform/settings.cpp
@@ -180,6 +180,14 @@ exit:
     }
 }
 
+void otPlatSettingsDeinit(otInstance *aInstance)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+
+    assert(sSettingsFd != -1);
+    VerifyOrDie(close(sSettingsFd) == 0);
+}
+
 otError otPlatSettingsGet(otInstance *aInstance, uint16_t aKey, int aIndex, uint8_t *aValue, uint16_t *aValueLength)
 {
     OT_UNUSED_VARIABLE(aInstance);
@@ -484,6 +492,7 @@ int main()
         assert(otPlatSettingsGet(instance, 0, 0, NULL, NULL) == OT_ERROR_NOT_FOUND);
     }
     otPlatSettingsWipe(instance);
+    otPlatSettingsDeinit(instance);
 
     return 0;
 }
diff --git a/tests/fuzz/fuzzer_platform.c b/tests/fuzz/fuzzer_platform.c
index b8d3abd99..69de2c039 100644
--- a/tests/fuzz/fuzzer_platform.c
+++ b/tests/fuzz/fuzzer_platform.c
@@ -353,6 +353,11 @@ void otPlatSettingsInit(otInstance *aInstance)
     OT_UNUSED_VARIABLE(aInstance);
 }
 
+void otPlatSettingsDeinit(otInstance *aInstance)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+}
+
 otError otPlatSettingsBeginChange(otInstance *aInstance)
 {
     OT_UNUSED_VARIABLE(aInstance);
diff --git a/tests/unit/test_platform.cpp b/tests/unit/test_platform.cpp
index ac3286212..3e7b1c933 100644
--- a/tests/unit/test_platform.cpp
+++ b/tests/unit/test_platform.cpp
@@ -487,6 +487,11 @@ void otPlatSettingsInit(otInstance *aInstance)
     OT_UNUSED_VARIABLE(aInstance);
 }
 
+void otPlatSettingsDeinit(otInstance *aInstance)
+{
+    OT_UNUSED_VARIABLE(aInstance);
+}
+
 otError otPlatSettingsBeginChange(otInstance *aInstance)
 {
     OT_UNUSED_VARIABLE(aInstance);