S73 may refer to:

Aircraft

* Bernard S-73, a French racing monoplane * Savoia-Marchetti S.73, an Italian airliner *

Sikorsky S-73 The Sikorsky S-73 was a proposed aircraft design to meet the United States Army requirement in 1970 for a Heavy Lift Helicopter (HLH) capable of carrying , a lifting capacity more than twice that of Sikorsky's most powerful helicopter at that tim ...

, an American helicopter proposal

Submarines

* , of the Royal Canadian Navy * , of the Indian Navy * , of the Israeli Navy

Other uses

* County Route S73 (Bergen County, New Jersey) * S73, a postcode district for Barnsley, England {{Letter-NumberCombDisambig