The Lagrangian Grassmannian, denoted by , is a homogeneous space of Lagrangian subspaces of a complex symplectic vector space of dimension . This talk is devoted to the small quantum cohomology ring of . More concretely, we shall focus on the quantum structure constants and explain how to compute them. Geometrically, these are , genus Gromov-Witten invariants of which count the number of rational curves contained in intersecting with three Schubert varieties in general position. By the quantum-classical principle of Buch-Kresch- Tamvakis, we show that the quantum structure constants can be computed as intersection numbers on the usual Grassmannian.