diff --git a/calendar-widget/README.md b/calendar-widget/README.md
index 0c2b940..e354c07 100644
--- a/calendar-widget/README.md
+++ b/calendar-widget/README.md
@@ -12,6 +12,7 @@ Calendar widget for Awesome WM - slightly improved version of the `wibox.widget.
 | theme     | `naughty` | The theme to use          |
 | placement | `top`     | The position of the popup |
 | radius    |  8        | The popup radius          |
+| start_sunday | false  | Start the week on Sunday  |
 
  - themes:
 
@@ -37,6 +38,10 @@ Calendar widget for Awesome WM - slightly improved version of the `wibox.widget.
 
   ![calendar_bottom_right](./calendar_bottom_right.png)
 
+ - setup first day of week
+
+   By setting `start_sunday` to true:
+   ![calendar_start_sunday](./calendar_start_sunday.png)
 
  - mouse support:
     move to the next and previous month. Using mouse buttons or scroll wheel.
@@ -44,13 +49,13 @@ Calendar widget for Awesome WM - slightly improved version of the `wibox.widget.
     You can configure this by specifying the button to move to next/previous.
     Usually these are configured as follows. If you want to use other mouse buttons, you can find their number using `xev`.
 
-    | number | button |
-    |--------|--------|
-    | 4      | scroll up |
-    | 5      | scroll down |
-    | 1      | left click |
-    | 2 | right click |
-    | 3 | middles click |
+    | number | button        |
+    |--------|---------------|
+    | 4      | scroll up     |
+    | 5      | scroll down   |
+    | 1      | left click    |
+    | 2      | right click   |
+    | 3      | middles click |
 
     By default `previous_month_button` is 5, `next_month_button` is 4.
 
@@ -71,6 +76,7 @@ local cw = calendar_widget()
 local cw = calendar_widget({
     theme = 'outrun',
     placement = 'bottom_right',
+    start_sunday = true,
     radius = 8,
 -- with customized next/previous (see table above)
     previous_month_button = 1,
diff --git a/calendar-widget/calendar.lua b/calendar-widget/calendar.lua
index d62f52b..4bb637f 100644
--- a/calendar-widget/calendar.lua
+++ b/calendar-widget/calendar.lua
@@ -97,6 +97,7 @@ local function worker(user_args)
     local radius = args.radius or 8
     local next_month_button = args.next_month_button or 4
     local previous_month_button = args.previous_month_button or 5
+    local start_sunday = args.start_sunday or false
 
     local styles = {}
     local function rounded_shape(size)
@@ -184,6 +185,7 @@ local function worker(user_args)
         font = beautiful.get_font(),
         fn_embed = decorate_cell,
         long_weekdays = true,
+        start_sunday = start_sunday,
         widget = wibox.widget.calendar.month
     }