diff --git a/include/boost/asio/detail/dev_poll_reactor.hpp b/include/boost/asio/detail/dev_poll_reactor.hpp
index 97454df7..aa6add33 100644
--- a/include/boost/asio/detail/dev_poll_reactor.hpp
+++ b/include/boost/asio/detail/dev_poll_reactor.hpp
@@ -143,6 +143,12 @@ public:
       typename timer_queue<Time_Traits>::per_timer_data& timer,
       std::size_t max_cancelled = (std::numeric_limits<std::size_t>::max)());
 
+  // Cancel the timer operations associated with the given key.
+  template <typename Time_Traits>
+  void cancel_timer_by_key(timer_queue<Time_Traits>& queue,
+      typename timer_queue<Time_Traits>::per_timer_data* timer,
+      void* cancellation_key);
+
   // Move the timer operations associated with the given timer.
   template <typename Time_Traits>
   void move_timer(timer_queue<Time_Traits>& queue,
diff --git a/include/boost/asio/detail/impl/dev_poll_reactor.hpp b/include/boost/asio/detail/impl/dev_poll_reactor.hpp
index 767851a8..e1720b67 100644
--- a/include/boost/asio/detail/impl/dev_poll_reactor.hpp
+++ b/include/boost/asio/detail/impl/dev_poll_reactor.hpp
@@ -77,6 +77,18 @@ std::size_t dev_poll_reactor::cancel_timer(timer_queue<Time_Traits>& queue,
   return n;
 }
 
+template <typename Time_Traits>
+void dev_poll_reactor::cancel_timer_by_key(timer_queue<Time_Traits>& queue,
+    typename timer_queue<Time_Traits>::per_timer_data* timer,
+    void* cancellation_key)
+{
+  boost::asio::detail::mutex::scoped_lock lock(mutex_);
+  op_queue<operation> ops;
+  queue.cancel_timer_by_key(timer, ops, cancellation_key);
+  lock.unlock();
+  scheduler_.post_deferred_completions(ops);
+}
+
 template <typename Time_Traits>
 void dev_poll_reactor::move_timer(timer_queue<Time_Traits>& queue,
     typename timer_queue<Time_Traits>::per_timer_data& target,