  In this paper, we study the effect of the minimal length on neutrino
oscillation in a static magnetic field. In the framework of the generalized
uncertainty principle, we reformulate the Hamiltonian for a relativistic
neutrino moving in a magnetic field oriented along the z-direction of Cartesian
coordinates. Using the modified energy spectrum, we obtain the oscillation
probability for different neutrino flavors. In addition, we obtain the energy
differences for the neutrino-mass eigenstates. We find that the energy and
energy difference depend on the minimal length parameter {\alpha}, and the
energy difference becomes independent of {\alpha} when the magnetic field is
not present. In addition, we find that the modified probability of oscillation
differs from the usual probability of oscillation if a magnetic field is
present. Using the current experimental result, we estimate the upper bound on
the deformation parameter and the minimal length, and find that the upper bound
on the minimal length scale is less than the electroweak scale. If the minimal
length is at Planck scale, the minimal length formalism leads to the same
result as a quantum theory of gravity with an $SU(2)_{L} \times U(1)$ effective
invariant dimension-5 Lagrangian including neutrino and Higgs fields.
