diff --git a/pushover.py b/pushover.py
index f539992..8a4dffb 100755
--- a/pushover.py
+++ b/pushover.py
@@ -4,6 +4,12 @@ import argparse
 import requests
 
 
+def optional_int(value):
+    """Convert string to int, treating empty strings as None"""
+    if value == '':
+        return None
+    return int(value)
+
 def get_args():
     parser = argparse.ArgumentParser()
     parser.add_argument('--message', type=str, help='Message text')
@@ -11,7 +17,7 @@ def get_args():
     parser.add_argument('--url', type=str, help='Supplementary URL to show with your message')
     parser.add_argument('--url_title', type=str, help='title for your supplementary URL, otherwise just the URL is shown')
     parser.add_argument('--device', type=str, help='Device name to send the message directly to')
-    parser.add_argument('--priority', type=int, help='Notification priority (low-to-high: -2 to 1)')
+    parser.add_argument('--priority', type=optional_int, help='Notification priority (low-to-high: -2 to 1)')
     parser.add_argument('--sound', type=str, help='The name of a supported sound (https://pushover.net/api#sounds; custom sounds are supported)')
     args = parser.parse_args()
     return args
@@ -48,7 +54,7 @@ def main():
     if device:
         payload['device'] = device
     if priority:
-        payload['priority'] = priority
+        payload['priority'] = str(priority)
     if sound:
         payload['sound'] = sound