The present study aimed to investigate the relationship of attachment styles with achievement motivation and academic performance in math among high school students in Khash.The descriptive-correlational research method was applied. The study populationincluded all high school students in Khash (N=1820). Random sampling was used to select the sample size. According to the Morgan’s table, the sample size of a population with 1820 subjects is 320. To collect the necessary data related to the research variables, two standard questionnaires including Hazan and Shaver’s attachment styles survey with 15 items, Hermans’s (1970) achievement motivation questionnaire with 29 items together withlearners’ math scores were used. For data analysis, statistical tests relevant to research hypotheses, including Pearson correlation coefficient, one-sample t-test and one way ANOVA were applied. All statistical calculations were performed using SPSS version 21. Findings suggested that there was a significant negative relationship between achievement motivation and math performance with avoidant and preoccupied attachment styles; however, these two had a positive significant relationship with secure attachment style. The results also revealed a positive significant correlation betweenachievement motivation and mathematics performance. The level of female students’ achievement motivation was below average. However, regarding the educationalgrade, high school female students’ achievement motivation did not vary.