Colobanthus kerguelensis is a low-growing, moss-like flowering cushion plant in the family Caryophyllaceae, found on subantarctic islands in the southern Indian Ocean.

The specific epithet refers to the type locality – the Kerguelen Islands.

[2] Colobanthus kerguelensis is a perennial herb that forms loose clumps or cushions up to 65 mm in diameter.

The slender, freely branching stems lack adventitious roots.

[2] As well as on Kerguelen, Colobanthus kerguelensis occurs on the Crozet, Prince Edward, and Heard Islands.