diff --git a/lib/logtail/log_devices/http.rb b/lib/logtail/log_devices/http.rb
index 331bf34..48b6edf 100755
--- a/lib/logtail/log_devices/http.rb
+++ b/lib/logtail/log_devices/http.rb
@@ -119,13 +119,13 @@ def flush
       # Closes the log device, cleans up, and attempts one last delivery.
       def close
         # Kill the flush thread immediately since we are about to flush again.
-        @flush_thread.kill if @flush_thread
+        @flush_thread.kill.join if @flush_thread
 
         # Flush all remaining messages
         flush
 
         # Kill the request queue thread. Flushing ensures that no requests are pending.
-        @request_outlet_thread.kill if @request_outlet_thread
+        @request_outlet_thread.kill.join if @request_outlet_thread
       end
 
       def deliver_one(msg)
diff --git a/spec/logtail/log_devices/http_spec.rb b/spec/logtail/log_devices/http_spec.rb
index fad540e..9ae0743 100755
--- a/spec/logtail/log_devices/http_spec.rb
+++ b/spec/logtail/log_devices/http_spec.rb
@@ -57,10 +57,8 @@
       http.send(:ensure_flush_threads_are_started)
       http.close
       thread = http.instance_variable_get(:@flush_thread)
-      sleep 0.1 # too fast!
       expect(thread).to_not be_alive
       thread = http.instance_variable_get(:@request_outlet_thread)
-      sleep 0.1 # too fast!
       expect(thread).to_not be_alive
     end