| Kardiotissa | |
| Native Name: | Καρδιώτισσα |
| Native Name Lang: | el |
| Coordinates: | 36.63°N 25.02°W |
| Map: | Greece |
| Archipelago: | Cyclades |
| Country: | Greece |
| Country Admin Divisions Title: | Region |
| Country Admin Divisions: | South Aegean |
| Country Admin Divisions Title 1: | Regional unit |
| Country Admin Divisions 1: | Thira |
| Country Admin Divisions Title 2: | Municipality |
| Population: | 0 |
| Population As Of: | 2001 |
| Postal Code: | 840 10 |
| Area Code: | 22860 |
| Registration Plate: | EM |
Kardiotissa (Greek, Modern (1453-);: Καρδιώτισσα), anciently, Lagusa or Lagousa (Greek, Ancient (to 1453);: Λάγουσα) or Lagussa or Lagoussa (Λαγοῦσσα), is a Greek island in the Cyclades. It is uninhabited and administratively a part of the island community of Sikinos. It lies midway between that island and the island of Folegandros.