This study investigated whether transfer from L2 to L1 in reading occurs, and if so, which reading sub-skills are transferred into L1 reading. The aim is to identify the role of second language reading skills in L1 reading skills by means of transfer. In addition, the positive effects of the second language transfer to the first language in the context of reading skills and sub-skills were analyzed. Fifty-three native Turkish-speaking adults English language learners were tested in this study. These participants were university students who had the same L1 Turkish proficiency backgrounds. While 26 students took L2 reading courses for four months, the other 27 students did not take any L2 reading courses. After four months of L2 reading courses, these two groups were given a standard L1 (Turkish) reading test. The Turkish reading test included vocabulary, comprehension, grammar and reading sub-skills questions. The results revealed that L1 reading skills were affected positively by the L2 reading skill transfer. The study reveals which L1 reading sub-skills are more developed by L2 reading skills transfer. For further studies, the correlations in L1 and L2 courses may open a way in language curriculum design. Both courses can be designed as an adjunct course formulated on the skill-based syllabus model, and reading skills can be transferred cross-linguistically. Thus, L2 reading proficiency will be transferred to L1 proficiency.