diff --git a/include/libopencm3/stm32/iwdg.h b/include/libopencm3/stm32/iwdg.h
index 4d5fb4c0..a9012225 100644
--- a/include/libopencm3/stm32/iwdg.h
+++ b/include/libopencm3/stm32/iwdg.h
@@ -32,6 +32,8 @@
 #       include <libopencm3/stm32/f4/iwdg.h>
 #elif defined(STM32L1)
 #       include <libopencm3/stm32/l1/iwdg.h>
+#elif defined(STM32L4)
+#       include <libopencm3/stm32/l4/iwdg.h>
 #else
 #       error "stm32 family not defined."
 #endif
diff --git a/include/libopencm3/stm32/l4/iwdg.h b/include/libopencm3/stm32/l4/iwdg.h
new file mode 100644
index 00000000..5dac9043
--- /dev/null
+++ b/include/libopencm3/stm32/l4/iwdg.h
@@ -0,0 +1,52 @@
+/** @defgroup iwdg_defines IWDG Defines
+ *
+ * @brief <b>Defined Constants and Types for the STM32L4xx Independent Watchdog
+ * Timer</b>
+ *
+ * @ingroup STM32L4xx_defines
+ *
+ * @version 1.0.0
+ *
+ * @date 18 December 2017
+ *
+ * LGPL License Terms @ref lgpl_license
+ */
+
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LIBOPENCM3_IWDG_H
+#define LIBOPENCM3_IWDG_H
+
+#include <libopencm3/stm32/common/iwdg_common_all.h>
+
+/* --- IWDG registers ------------------------------------------------------ */
+
+/* Window register (IWDG_WINR) */
+#define IWDG_WINR                               MMIO32(IWDG_BASE + 0x10)
+
+/* --- IWDG_SR values ------------------------------------------------------ */
+
+/* WVU: Watchdog counter window value update */
+#define IWGD_SR_WVU                     (1 << 2)
+
+/* --- IWDG_WIN values ----------------------------------------------------- */
+
+/* Bits 11:0 WIN[11:0]: Watchdog counter window value */
+
+#endif
+
diff --git a/lib/stm32/l4/Makefile b/lib/stm32/l4/Makefile
index 54878bf0..dbfc1f10 100644
--- a/lib/stm32/l4/Makefile
+++ b/lib/stm32/l4/Makefile
@@ -50,6 +50,7 @@ OBJS            += timer_common_all.o
 OBJS            += i2c_common_v2.o
 OBJS            += usart_common_all.o usart_common_v2.o
 OBJS            += dma_common_l1f013.o
+OBJS            += iwdg_common_all.o
 
 VPATH += ../../usb:../:../../cm3:../common
 VPATH += ../../ethernet