A robust adaptive output feedback (OFB) dynamic inversion control strategy is presented that achieves global asymptotic tracking of a reference model. The considered system contains linearly parameterizable uncertainty in the state and input matrices. The dynamic model also includes an unknown, nonlinear disturbance, which does not satisfy the linear-in-the-parameters assumption. A continuous tracking controller is designed to mitigate the nonlinear disturbance and inversion error, and a Lyapunov-based adaptive law is utilized to compensate for the parametric uncertainty. Global asymptotic tracking of the measurable output states is proven via Lyapunov stability analysis, and high-fidelity simulation results are provided to illustrate the applicability and performance of the developed control law for an unmanned air vehicle (UAV).