<p>This paper investigates an inverse problem of simultaneously identifying the fractional order and the boundary condition in a time-fractional diffusion equation from nonlocal integral observation data. By exploiting a uniform bound for the Mittag-Leffler function, together with the Laplace transform and analytic continuation techniques, we establish the uniqueness of the inverse problem and prove the Lipschitz continuity of the associated direct operator. Subsequently, a discrete Levenberg–Marquardt regularization method is employed to simultaneously recover the fractional order and the boundary condition. Finally, several numerical experiments are presented to demonstrate the effectiveness and robustness of the proposed approach.</p>