A wind turbine blade is described having a pitch system coupling which is adapted to allow fasteners, such as bolts, of such a coupling to be tightened from the inside of the blade. This removes the need for relatively difficult and expensive external maintenance operations to tighten pitch coupling bolts. The coupling is arranged to present first and second internal bearing surfaces, against which the bolts of the pitch coupling can be tightened. The coupling may comprise a shaped end portion of an inner blade section, and/or the pitch system may comprise an additional bolting collar to facilitate this arrangement.