Given a symplectic manifold $M$, we may define an operad structure on the the
spaces $\op^k$ of the Lagrangian submanifolds of $(\bar{M})^k\times M$ via
symplectic reduction. If $M$ is also a symplectic groupoid, then its
multiplication space is an associative product in this operad. Following this
idea, we provide a deformation theory for symplectic groupoids analog to the
deformation theory of algebras. It turns out that the semi-classical part of
Kontsevich's deformation of $C^\infty(\R^d)$ is a deformation of the trivial
symplectic groupoid structure of $T^*\R^d$.