Timed examinations continue to be a common educational assessment method employed to evaluate a student's knowledge, ability and skills in their subject area. Extra time is the most common adjustment that students with specific learning difficulties (SpLD) are granted in these exams. This adjustment aims to provide students with SpLD parity with their typically developing (TD) peers in exams by ensuring that the differences in scores between candidates reflect the differences in their subject ability and not in their speed. Numerous studies have been conducted with the aim of identifying whether or not extra time confers an advantage or enables students with SpLD to more accurately demonstrate their potential in exam situations. This article summarises the existing empirical research investigating the practice of granting this exam adjustment in order to identify what the current body of research concludes is the effect of receiving extended time on the results of candidates with SpLD by comparison with their TD peers. This investigation found no consensus of opinion, however, a pattern does emerge across all the studies as a whole, which suggests that the differences in outcome may be explained by differences in the appropriateness of the time limits imposed by each study.