Loellingite, also spelled löllingite, is an iron arsenide mineral with formula FeAs2.

The orthorhombic lollingite group includes the nickel iron arsenide rammelsbergite and the cobalt iron arsenide safflorite.

It also occurs in anhedral masses and tarnishes on exposure to air.

Loellingite was first described in 1845 at the Lölling district in Carinthia, Austria, for which it was named.

It occurs in mesothermal ore deposits associated with skutterudite, native bismuth, nickeline, nickel-skutterudite, siderite and calcite.