503 may refer to:
- 503 (number)
- 503, a year
- 503, a track by Hans Zimmer on the Angels & Demons soundtrack
- 503 Service Unavailable, an HTTP status code
- Area code 503, a North American telephone area code in northwestern Oregon
- BMW 503, a luxury car
- Country code +503, for El Salvador
- FN 503, a semi-automatic pistol manufactured by FN Herstal
- A type of jeans, commonly in Levi's and Edwin
- A type of steel used for making bicycle frames
| This disambiguation page lists articles associated with the same number.
If an internal link led you here, you may wish to change the link to point directly to the intended article.