diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index f2ac41c..4a9d0ef 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -660,6 +660,39 @@
 #define POLARSSL_SSL_TRUNCATED_HMAC
 
 /**
+ * \def POLARSSL_THREADING_ALT
+ *
+ * Provide your own alternate threading implementation.
+ *
+ * Requires: POLARSSL_THREADING_C
+ *
+ * Uncomment this to allow your own alternate threading implementation.
+#define POLARSSL_THREADING_ALT
+ */
+
+/**
+ * \def POLARSSL_THREADING_DUMMY
+ *
+ * Provide a dummy threading implementation.
+ *
+ * Requires: POLARSSL_THREADING_C
+ *
+ * Uncomment this to enable code to compile like with threading enabled
+#define POLARSSL_THREADING_DUMMY
+ */
+
+/**
+ * \def POLARSSL_THREADING_PTHREAD
+ *
+ * Enable the pthread wrapper layer for the threading layer.
+ *
+ * Requires: POLARSSL_THREADING_C
+ *
+ * Uncomment this to enable pthread mutexes.
+#define POLARSSL_THREADING_PTHREAD
+ */
+
+/**
  * \def POLARSSL_X509_ALLOW_EXTENSIONS_NON_V3
  *
  * If set, the X509 parser will not break-off when parsing an X509 certificate
@@ -1436,6 +1469,27 @@
 #define POLARSSL_SSL_TLS_C
 
 /**
+ * \def POLARSSL_THREADING_C
+ *
+ * Enable the threading abstraction layer.
+ * By default PolarSSL assumes it is used in a non-threaded environment or that
+ * contexts are not shared between threads. If you do intend to use contexts
+ * between threads, you will need to enable this layer to prevent race
+ * conditions.
+ *
+ * Module:  library/threading.c
+ *
+ * This allows different threading implementations (self-implemented or
+ * provided).
+ *
+ * You will have to enable either POLARSSL_THREADING_ALT,
+ * POLARSSL_THREADING_PTHREAD or POLARSSL_THREADING_DUMMY.
+ *
+ * Enable this layer to allow use of mutexes within PolarSSL
+#define POLARSSL_THREADING_C
+ */
+
+/**
  * \def POLARSSL_TIMING_C
  *
  * Enable the portable timing interface.
@@ -1784,6 +1838,32 @@
 #error "POLARSSL_SSL_SESSION_TICKETS_C defined, but not all prerequisites"
 #endif
 
+#if defined(POLARSSL_THREADING_DUMMY)
+#if !defined(POLARSSL_THREADING_C) || defined(POLARSSL_THREADING_IMPL)
+#error "POLARSSL_THREADING_DUMMY defined, but not all prerequisites"
+#endif
+#define POLARSSL_THREADING_IMPL
+#endif
+
+#if defined(POLARSSL_THREADING_PTHREAD)
+#if !defined(POLARSSL_THREADING_C) || defined(POLARSSL_THREADING_IMPL)
+#error "POLARSSL_THREADING_PTHREAD defined, but not all prerequisites"
+#endif
+#define POLARSSL_THREADING_IMPL
+#endif
+
+#if defined(POLARSSL_THREADING_ALT)
+#if !defined(POLARSSL_THREADING_C) || defined(POLARSSL_THREADING_IMPL)
+#error "POLARSSL_THREADING_ALT defined, but not all prerequisites"
+#endif
+#define POLARSSL_THREADING_IMPL
+#endif
+
+#if defined(POLARSSL_THREADING_C) && !defined(POLARSSL_THREADING_IMPL)
+#error "POLARSSL_THREADING_C defined, single threading implementation required"
+#endif
+#undef POLARSSL_THREADING_IMPL
+
 #if defined(POLARSSL_X509_USE_C) && ( !defined(POLARSSL_BIGNUM_C) ||  \
     !defined(POLARSSL_OID_C) || !defined(POLARSSL_ASN1_PARSE_C) ||      \
     !defined(POLARSSL_PK_PARSE_C) )
diff --git a/include/polarssl/error.h b/include/polarssl/error.h
index ab3d632..a64960c 100644
--- a/include/polarssl/error.h
+++ b/include/polarssl/error.h
@@ -53,6 +53,7 @@
  * MPI       7  0x0002-0x0010
  * GCM       2  0x0012-0x0014
  * BLOWFISH  2  0x0016-0x0018
+ * THREADING 3  0x001A-0x001E
  * AES       2  0x0020-0x0022
  * CAMELLIA  2  0x0024-0x0026
  * XTEA      1  0x0028-0x0028
diff --git a/include/polarssl/threading.h b/include/polarssl/threading.h
new file mode 100644
index 0000000..4afaeea
--- /dev/null
+++ b/include/polarssl/threading.h
@@ -0,0 +1,84 @@
+/**
+ * \file threading.h
+ *
+ * \brief Threading abstraction layer
+ *
+ *  Copyright (C) 2006-2013, Brainspark B.V.
+ *
+ *  This file is part of PolarSSL (http://www.polarssl.org)
+ *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
+ *
+ *  All rights reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef POLARSSL_THREADING_H
+#define POLARSSL_THREADING_H
+
+#include "config.h"
+
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define POLARSSL_ERR_THREADING_FEATURE_UNAVAILABLE         -0x001A  /**< The selected feature is not available. */
+#define POLARSSL_ERR_THREADING_BAD_INPUT_DATA              -0x001C  /**< Bad input parameters to function. */
+#define POLARSSL_ERR_THREADING_MUTEX_ERROR                 -0x001E  /**< Locking / unlocking / free failed with error code. */
+
+#if defined(POLARSSL_THREADING_DUMMY)
+typedef void threading_mutex_t;
+#endif
+
+#if defined(POLARSSL_THREADING_PTHREAD)
+#include <pthread.h>
+typedef pthread_mutex_t threading_mutex_t;
+#endif
+
+#if defined(POLARSSL_THREADING_ALT)
+/* You should define the threading_mutex_t type in your header */
+#include "threading_alt.h"
+
+/**
+ * \brief           Set your alternate threading implementation function
+ *                  pointers
+ *
+ * \param mutex_init    the malloc function implementation
+ * \param mutex_free    the free function implementation
+ * \param mutex_lock    the lock function implementation
+ * \param mutex_unlock  the unlock function implementation
+ *
+ * \return              0 if successful
+ */
+int threading_set_alt( int (*mutex_init)( threading_mutex_t * ),
+                       int (*mutex_free)( threading_mutex_t * ),
+                       int (*mutex_lock)( threading_mutex_t * ),
+                       int (*mutex_unlock)( threading_mutex_t * ) );
+#endif /* POLARSSL_THREADING_ALT_C */
+
+/*
+ * The function pointers for mutex_init, mutex_free, mutex_ and mutex_unlock
+ */
+extern int (*polarssl_mutex_init)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_free)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_lock)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_unlock)( threading_mutex_t *mutex );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* threading.h */