<p>Integral methods are used in boundary layer theory for the estimation of quantities such as displacement thickness, skin-friction drag, etc. In this paper, a momentum-integral equation is derived for magnetohydrodynamic (MHD) boundary layer flow over a semi-infinite, insulated flat plate under a transverse, uniform magnetic field. The predictions from integral solution are compared with those from similarity solution and numerical simulations. The closed-form integral solution, using two velocity profiles, compares very well&#xa0;with the solution of the similarity equation up to Stuart number (the ratio of the Lorentz force to the inertia force) of <i>N</i> = 0.2. The velocity profile and parameters such as skin-friction coefficient, displacement and momentum thickness, obtained from the integral solution agree with our similarity solution and numerical simulations of flat plate boundary layer flow. The displacement and momentum thickness decreases, and the skin friction coefficient increases with an increase in <i>N,</i> as expected. For large <i>N</i> (~ 100, 1000), the predictions from the integral solution agree with those obtained from similarity solution, numerical simulations as well as with the Hartmann layer velocity profile. The ratio of the skin-friction coefficient with and without magnetic field, obtained from integral solutions, is found to vary as <i>N</i>^1/2 as also predicted from scaling analysis. Our integral solution predicts a constant boundary layer (Hartmann layer) thickness in the limit of large <i>N,</i> and non-magnetic (hydrodynamic) integral solutions for <i>N</i> = 0, as special cases.</p>