diff --git a/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.c b/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.c
new file mode 100644
index 0000000000..5fee0aab39
--- /dev/null
+++ b/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2013-2016 ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Project:     CMSIS-RTOS RTX
+ * Title:       OS Event Observer
+ *
+ * -----------------------------------------------------------------------------
+ */
+#include "rt_OsEventObserver.h"
+
+/*
+ *  _____ _____  ____  __ _____
+ * |  ___|_ _\ \/ /  \/  | ____|
+ * | |_   | | \  /| |\/| |  _|
+ * |  _|  | | /  \| |  | | |___
+ * |_|   |___/_/\_\_|  |_|_____|
+ *
+ * FIXME:
+ * The osEventObs variable must be in protected memory. If not every box
+ * and box 0 can modify osEventObs to point to any handler to run code
+ * privileged. This issue is tracked at
+ * <https://github.com/ARMmbed/uvisor/issues/235>.
+ */
+const OsEventObserver *osEventObs;
+
+void osRegisterForOsEvents(const OsEventObserver *observer)
+{
+    static uint8_t has_been_called = 0;
+    if (has_been_called) {
+        return;
+    }
+    has_been_called = 1;
+
+    osEventObs = observer;
+}
diff --git a/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.h b/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.h
new file mode 100644
index 0000000000..899f319029
--- /dev/null
+++ b/rtos/TARGET_CORTEX/rtx5/RTX/Source/rt_OsEventObserver.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2013-2016 ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * -----------------------------------------------------------------------------
+ *
+ * Project:     CMSIS-RTOS RTX
+ * Title:       OS Event Observer
+ *
+ * -----------------------------------------------------------------------------
+ */
+#ifndef _RT_OS_EVENT_OBSERVER_H
+#define _RT_OS_EVENT_OBSERVER_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+    uint32_t version;
+    void (*pre_start)(void);
+    void *(*thread_create)(int thread_id, void *context);
+    void (*thread_destroy)(void *context);
+    void (*thread_switch)(void *context);
+} OsEventObserver;
+extern const OsEventObserver *osEventObs;
+
+void osRegisterForOsEvents(const OsEventObserver *observer);
+
+#ifdef __cplusplus
+};
+#endif
+
+#endif
+
+/** @}*/