diff --git a/include/semaphore.h b/include/semaphore.h
new file mode 100644
index 00000000..5393235e
--- /dev/null
+++ b/include/semaphore.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2020 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef KTF_SEMAPHORE_H
+#define KTF_SEMAPHORE_H
+
+#include <atomic.h>
+#include <ktf.h>
+
+struct sem {
+    atomic_t v;
+};
+typedef struct sem sem_t;
+
+#define MAX_SEMAPHORE_VALUE (_U32(-1) / 2)
+#define SEM_INIT(value)                                                                  \
+    {                                                                                    \
+        .v = {(value) }                                                                  \
+    }
+
+extern void sem_init(sem_t *sem, uint32_t value);
+extern bool sem_trywait(sem_t *sem);
+extern void sem_wait(sem_t *sem);
+extern void sem_post(sem_t *sem);
+
+#endif
\ No newline at end of file
diff --git a/lib/semaphore.c b/lib/semaphore.c
new file mode 100644
index 00000000..399e7df2
--- /dev/null
+++ b/lib/semaphore.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2020 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <mm/slab.h>
+#include <semaphore.h>
+
+void sem_init(sem_t *sem, uint32_t value) {
+    /* Do not allow more than 2^31-1 threads to access this semaphore */
+    BUG_ON(value > MAX_SEMAPHORE_VALUE);
+
+    atomic_set(&(sem->v), value);
+}
+
+bool sem_trywait(sem_t *sem) {
+    int64_t val;
+
+    if (atomic_read(&(sem->v)) > 0) {
+        val = atomic_dec_return(&(sem->v));
+        if (val >= 0) {
+            return true;
+        }
+        else {
+            atomic_inc(&(sem->v));
+        }
+    }
+
+    return false;
+}
+
+void sem_wait(sem_t *sem) {
+    while (!sem_trywait(sem)) {
+        cpu_relax();
+    }
+}
+
+void sem_post(sem_t *sem) { atomic_inc(&(sem->v)); }