This study aims to compare the reading comprehension skills of the bilingual students studying at the 4th Grade of the Primary School with the monolingual students studying at the 4th Grade. With this purpose, 303 students were included from the Black Sea Region, where mainly monolingual students studied and 247 students were included from the Eastern and South-eastern Regions, where bilingual students studied. Furthermore, in order to expand the scope of the research, it was intended to find out the views of class teachers about the reading comprehension skills of bilingual students. So in the research, the mixed method and the parallel pattern converging from the patterns of the mixed method were used. The research result presented a significant difference between the reading comprehension skills of the monolingual 4th grade students from the Black Sea Region and the students from the Eastern and South-eastern Regions. This difference was in favour of the monolingual students. On the other hand, reading comprehension skills of the 4th graders in the Eastern and South-eastern Regions did not significantly differ within itself depending on bilingualism.