Abstract: Meinong’s object theory is thought by many to be inconsistent (or even trivial). Indeed, its most straightforward formalisation in second-order logic is. However, contemporary logicians have developed more subtle formalisations of Meinong’s ideas, the so-called neo-Meinongian logics, that are provably consistent. In this talk, I review two of the main approachs, Nuclear Meinongianism and Dual Copula Meinongianism, and I develop a new one, based on a Meinongian instinct about complex properties. I present a consistent formal system based on second-order logic augmented with lambda-abstraction (an operator constructing complex properties) and a Meinongian operator m (which constructs Meinongian objects). I then mention an application of this formal system in philosophy of mathematics. More precisely, I show how to derive a non-standard set theory within the formal system and present some of its properties. This serves as a first step towards Meinongian foundations of mathematics, resembling Frege’s logicism.