Previous studies demonstrated that executive functions, facial emotion recognition, mindfulness, and adult attachment problems were found in patients with borderline personality disorders (BPD). However, there was a big gap to explain the effects of the culture, eye – contact, adult attachment styles, working memory deficits (WMD), and mindfulness on BPD. In the current study, there were two main objectives. The first was to explore to what extent culture, adult attachment styles, WMD, eye – contact, and mindfulness predict BPD. The second was to ascertain the effects of adult attachment styles on WMD, BPD, additional GARS, and mindfulness. In the study, there were 113 Turkish and 139 Russian participants. Participants fulfilled the adult executive functioning inventory (ADEXI – WMD), mindfulness, experience in close relationship questionnaire (ECR – R), the personality beliefs questionnaire PBQ – BPD, and the additional GARS scale. A psychological diagnosis, gender, employment status, marital status, and education level were nominal variables. A Pearson's correlation test, Independent T-Test, one–way ANOVA, multiple linear regression analysis, and serial mediation analysis were computed. Results showed that both cultures had a high score on WMD. Turkish participants had a higher level of avoidant attachment style, BPD, and eye–contact problems than Russian participants. The culture, adult attachment styles, and WMD explained 49 percent of the total variance of BPD. The culture, adult attachment styles, and additional GARS predicted 45 percent of the total variance of BPD. In the Russian sample, mindfulness was adjusted by BPD, WMD, avoidant, and anxious attachment styles, whereas, in the Turkish sample mindfulness was predicted by additional GARS and anxious attachment style. In both cultures, adult attachment styles mediated the relationship between WMD and BPD. The study concluded that culture has a significant impact on eye – contact, avoidant attachment style, and BPD. Mindfulness has a different role in both cultures, and the relationship between WMD and BPD can be controlled by adult attachment styles. Moreover, it was found that WMD is evident in both countries. Therefore, these results should be considered in the therapeutic setting.