Abstract The present study numerically investigates the oblique flow of a Walter-B type nano fluid over a convective surface. Effects of transversely applied magnetic field are also taken into account. The governing system is presented in the form of coupled differential equations by means of suitable similarity transformations which are then solved by using Spectral Quasilinearisation Method (QLM) and the Spectral Local Linearization Method (LLM). The results for velocities temperature as well as nano particle concentration are plotted against pertinent flow parameters. It is found that applied magnetic field M has opposite influence on normal and tangential components of local shear stress and it decays the local heat flux and mass flux rate at the stretching convective surface. Thermophoresis and Brownian diffusion effects on the local heat and mass flux rate are found to be non-similar in a quantitative sense. In order to signify the validity of current numerical scheme, a remarkable agreement is presented with the previous literature for some limiting cases.