diff --git a/40-touchpad-cmt.conf b/40-touchpad-cmt.conf
index 01fd9fd..4df97fd 100644
--- a/40-touchpad-cmt.conf
+++ b/40-touchpad-cmt.conf
@@ -292,6 +292,10 @@
     Option          "Palm Filter Top Edge Enable" "1"
     Option          "Smooth Accel" "1"
     Option          "Tap Minimum Pressure" "20.0"
+
+    # Touch size increases with finger count, so ignore touch size for
+    # detecting palms if there are multiple touches.
+    Option          "Multiple Palm Width" "200.0"
 EndSection
 
 Section "InputClass"