diff --git a/libraries/AP_HAL/GPIO.cpp b/libraries/AP_HAL/GPIO.cpp
index 062a2c9a99..62e5ecec93 100644
--- a/libraries/AP_HAL/GPIO.cpp
+++ b/libraries/AP_HAL/GPIO.cpp
@@ -6,6 +6,15 @@
 
 extern const AP_HAL::HAL& hal;
 
+AP_HAL::PWMSource::~PWMSource()
+{
+    if (interrupt_attached) {
+        // Assume this is always successful
+        hal.gpio->detach_interrupt(_pin);
+        interrupt_attached = false;
+    }
+}
+
 bool AP_HAL::PWMSource::set_pin(int16_t new_pin, const char *subsystem)
 {
     if (new_pin == _pin) {
diff --git a/libraries/AP_HAL/GPIO.h b/libraries/AP_HAL/GPIO.h
index 5bbd446848..1e519e5b7c 100644
--- a/libraries/AP_HAL/GPIO.h
+++ b/libraries/AP_HAL/GPIO.h
@@ -19,6 +19,9 @@ public:
 class AP_HAL::PWMSource {
 public:
 
+    // Destructor detaches interrupt
+    ~PWMSource();
+
     bool set_pin(int16_t new_pin, const char *subsystem);
     int16_t pin() const { return _pin; }  // returns pin this is attached to