The purpose of this study is to examine irrational beliefs in romantic relationships as the predictor of aggression in emerging adults. The study is a quantitative study done using the relational survey model. The study group is composed of 351 fourth-year students, 201 females and 150 males, who were attending three universities in Central Anatolia during the 2016-2017 academic year. In order to collect the study data, 23-item "KAR-YA Aggression Scale with four sub-dimensions (Physical Aggression, Hostility, Anger, Verbal Aggression) was used. 30-item "Irrational Romantic Relationship Beliefs Inventory" with six dimensions (Over Expectations, Use of Social Time, Mind Reading, Different Thinking, Physical Intimacy, Gender Differences) was used to determine the irrational beliefs in romantic relationships. Also, "Personal Information Form" was used to obtain the participants' personal and socio-economic information. The data collected was analyzed using the SPSS 18 package program. T-test analysis was conducted to find the correlation and the gender differences between aggression and irrational beliefs in romantic relationships, and multi-hierarchical regression analysis was conducted to determine whether irrational beliefs in romantic relationships predict aggression or not. When the study findings are examined, it is seen that males' aggression levels and their irrational expectation regarding the social and free time activities are higher. In addition, in explaining emerging adults' aggression sex is a significant predictor of different thinking and gender differences variables from the IRBI sub-dimensions.