qpOASES is an open-source C++ implementation of the recently proposed online active set strategy for solving quadratic programming (QP) problems. It has several theoretical features that make it particularly suited for model predictive control (MPC) applications. Further numerical modifications have made qpOASES a reliable QP solver, even when tackling semi-definite, ill-posed or degenerated QP problems. Moreover, several interfaces to third-party software make qpOASES easy-to-use even for users without knowledge of C/C++.