This paper is dedicated to the regularity criteria of weak solutions to the three‐dimensional incompressible magnetohydrodynamics system in terms of only two velocity components. It is proved that the weak solution (u,b) is smooth on (0,T], provided that
∇u1,∇u2∈L43−2sfalse(0,T;trueB˙∞,∞−sfalse(ℝ3false)false).3emwith.3em0