diff --git a/hwdb/70-mouse.hwdb b/hwdb/70-mouse.hwdb
index d8215a61798..70a7fb98d13 100644
--- a/hwdb/70-mouse.hwdb
+++ b/hwdb/70-mouse.hwdb
@@ -47,6 +47,7 @@
 #    ID_INPUT_TRACKBALL
 #    MOUSE_DPI
 #    MOUSE_WHEEL_CLICK_ANGLE
+#    MOUSE_WHEEL_CLICK_ANGLE_HORIZ
 #
 #########################################
 #         ID_INPUT_TRACKBALL            #
@@ -104,6 +105,14 @@
 #
 # Most mice have a 15 degree click stop (24 clicks per full rotation).
 #
+#########################################
+#       MOUSE_WHEEL_CLICK_ANGLE_HORIZ   #
+#########################################
+#
+# Identical to MOUSE_WHEEL_CLICK_ANGLE but for the horizontal scroll wheel.
+# This property may only be specified if the angle for the horizontal
+# scroll wheel differs from the vertical wheel. If so, *both* click angles
+# must be specified.
 
 #
 # Sort by brand, type (usb, bluetooth), DPI, frequency.
@@ -344,9 +353,14 @@ mouse:usb:v046dpc52b:name:Logitech Unifying Device. Wireless PID:402d:
 
 # Logitech Performance MX
 mouse:usb:v046dp101a:name:Logitech Performance MX:
+ MOUSE_DPI=1000@166
+
 # Logitech MX Master
+# Horiz wheel has 14 stops, angle is rounded up
 mouse:usb:v046dp4041:name:Logitech MX Master:
  MOUSE_DPI=1000@166
+ MOUSE_WHEEL_CLICK_ANGLE=15
+ MOUSE_WHEEL_CLICK_ANGLE_HORIZ=26
 
 # Logitech MK260 Wireless Combo Receiver aka M-R0011
 mouse:usb:v046dpc52e:name:Logitech USB Receiver:
diff --git a/hwdb/parse_hwdb.py b/hwdb/parse_hwdb.py
index 99d034b4e05..fc23a5d0259 100755
--- a/hwdb/parse_hwdb.py
+++ b/hwdb/parse_hwdb.py
@@ -82,6 +82,7 @@ def property_grammar():
     setting = Optional('*')('DEFAULT') + INTEGER('DPI') + Suppress('@') + INTEGER('HZ')
     props = (('MOUSE_DPI', Group(OneOrMore(setting('SETTINGS*')))),
              ('MOUSE_WHEEL_CLICK_ANGLE', INTEGER),
+             ('MOUSE_WHEEL_CLICK_ANGLE_HORIZ', INTEGER),
              ('ID_INPUT_TRACKBALL', Literal('1')),
              ('POINTINGSTICK_SENSITIVITY', INTEGER),
              ('POINTINGSTICK_CONST_ACCEL', REAL),