The instability of a column under axial load is well known. A similar phenomenon is discussed in this paper for a beam-plate in a transverse magnetic field. Experiments show that the beam may buckle (in the sense of an Euler column) when the uniform magnetic field strength reaches a critical value. A mathematical model is proposed with distributed magnetic torques along the plate. A nontrivial adjacent equilibrium configuration satisfying the magnetostatic field equations is shown to exist for characteristic values of the external magnetic field. Results as predicted from this model compare favorably with experiments.