Early seeds of language variation studies were planted near the beginning of the 1960s under the influence of William Labov who is generally regarded as the founder of the discipline of variationist sociolinguistics which deals with language variations caused by linguistic and non-linguistic factors. With many other branches of linguistics, studies of language variation were also extended to the field of SLA and thereby studies of interlanguage or L2 learners’ language variation came into fashion. Almost all studies that have been conducted in this area are in association with variation in speech production and development of sociolinguistic competence and there are few studies which were devoted to the influence of linguistic or non-linguistic factors on variation in first and second language comprehension. This study, therefore, attempts to investigate the influence of text variation (in terms of narrative and non-narrative) on EFL learners’ reading comprehension ability. Doing so, 45 Persian native-speaking university students majoring in English translation at Arak university, Iran, were selected from among 67 ones and put into two homogeneous intact experimental and control groups (consisting of 21 and 24 participants, respectively). From a large body of existing texts, three narrative and three non-narrative texts (each between 1373 to 1622 words) with Flesch Reading Ease scores ranged from 66.83 to 73.90 were selected and used as tasks of elicitation. Statistical results, under the influence of existing variation between narratives and non-narratives, indicated significant difference between the experimental and control groups’ reading comprehension test scores from pretest to post test. Possible reasons for developed variation in reading comprehension ability and implications of the findings for language teaching are discussed. - See more at: http://www.sciencedomain.org/abstract.php?iid=431&id=21&aid=3676#sthash.ylr88PWt.dpuf