In the present study, contents of Persian textbooks of junior high school (seventh, eighth and ninth grades) were examined regarding the use of lexical coherence tools within the framework of Halliday and Hasan's Functional linguistics theory (1976). The research was conducted in a content analysis method and was descriptive. From each of the three books, three chapters were randomly selected. All lexical coherence tools were identified and tallied in the textbooks. The percentage of occurrence of each instrument was also obtained. The results showed that in the seventh, eighth, and ninth grade Persian books 158, 125, and 120 lexical coherence tools were used, respectively. In the seventh grade book, collocations and opposites were the most and the least commonly used instruments, respectively. In the eighth grade book, collocation and synonymy were the most and the least used instruments, respectively. In the ninth grade books, hyponymy and collocation were the most and the least used instruments, respectively. For more accurate statistical analysis, Chi-square test was used to explore the distribution of lexical coherence tools in each of the books. Based on the results obtained at the level of p <0. 05, there was a significant difference between the distribution of lexical coherence instruments in each of the books.