diff --git a/sumpy/fmm.py b/sumpy/fmm.py
index bd1c51d9b8050529c27174fdf068ffafbb766351..a233175686f2c395fe7783235ddeb5e351b09ff0 100644
--- a/sumpy/fmm.py
+++ b/sumpy/fmm.py
@@ -177,7 +177,8 @@ class SumpyTimingFuture(object):
                     stacklevel=3)
             return TimingResult(wall_elapsed=None)
 
-        pyopencl.wait_for_events(self.events)
+        if self.events:
+            pyopencl.wait_for_events(self.events)
 
         result = 0
         for event in self.events: