We present R-band photometry of the SW Sex-type cataclysmic variable WX Arietis made in October 1995 and August 1998-February 1999. Contrary to previous results, we find that WX Ari is an eclipsing system with an orbital inclination of i =~ 72o. The R-band light curves display highly variable, shallow eclipses ~ 0.15-mag deep and =~ 40 min long. The observed eclipse depth suggests a partial eclipse of the accretion disc. The light curves also show a wide dip in brightness centred at orbital phase varphi ~ 0.75 and a hump close to the opposite phase at varphi ~ 0.2. The observed dip may be explained by the probable vertical thickening of the outer rim of the accretion disc downstream from the bright spot. We also demonstrate that the disc brightness in all SW Sex systems is nearly the same. This implies that the orbital inclination of these systems is only a function of eclipse depth. Based on observations made with the Optical Ground Station (OGS) and the IAC--80 telescopes, operated on the island of Tenerife by the European Space Agency (ESA) and the Ins-ti-tu-to de Astrof\'i sica de Canarias (IAC), respectively, at the Spanish Observatorio del Teide and with the Jacobus Kapteyn Telescope (JKT), operated on the island of La Palma by PPARC at the Spanish Observatorio del Roque de los Muchachos.