Robust autopilot design for bank-to-turn (BTT) missiles under time-varying aerodynamic parameters, heavy nonlinear crossing couplings and external disturbances is investigated in this article by employing a distributed composite control framework. The dynamics of the BTT missiles are separated into three subsystems from the roll, yaw and pitch channels. For each subsystem, a composite control framework consists of a low-level state feedback stabilizer, a high-level model predictive controller and a feedforward compensator based on a disturbance observer. Simulation results demonstrate that compared with the baseline control and traditional integral control approaches, the proposed control strategy exhibits promising guidance command tracking and robustness against external disturbances, nonlinear crossing couplings and aerodynamic parameter perturbations.