The purpose of the study was to predict individual intentions to leave science, technology, engineering, and mathematics (STEM) field jobs. Psychological predictors were gender, the need to belong, self-esteem, perceived personal discrimination, and perceived group discrimination. We used the Amazon Mechanical Turk to recruit participants and Survey Monkey to conduct an online survey. Participants were 174 men and women who worked or studied in STEM fields. Two-step hierarchical linear regression analyses were performed to analyze the data. As a result, we found that all predictors mentioned above accounted for the variance in the intention to leave a job. Self-esteem and perceived personal discrimination were critical predictors for men in STEM fields; self-esteem and perceived group discrimination were critical predictors for women in STEM fields. For women, interestingly, the interaction effect of the need to belong and self-esteem added an additional variance in predicting the intention to leave a job. The need to belong buffered the effect of self-esteem on the intention of STEM women to leave a job. Thus, it might be that STEM women with low self-esteem are more likely to change a job if their need to belong is not fulfilled. v ACKNOWLEDGEMENTS This thesis is the result of many individuals' efforts. First, I give my sincerest gratitude to my supervisor, Dr. Greg Feist, who has supported me throughout the thesis process with inspiration, knowledge, and patience. Without his encouragement and effort, I would not have completed this thesis. I would like to thank Dr. Ronald Rogers who knew about my obstacles as an international student. I always appreciated the empathetic support and practical advice he instilled in me. He also taught me the fundamentals of psychological research and the attitude necessary to be an experimental psychologist. I would like to thank Dr. Sean Laraway for his comments on this thesis and for offering me a teaching assistant position in the statistics lab. This opportunity enabled me to build confidence in my English communication with students and to experience the joy of teaching statistics. I would also like to thank Dr. Alvarez, Dr. Asuncion, and Dr. Tokunaga for their development, statistics, and social cognition seminars and for opening my eyes to the connection of theory and scientific research methods. With affection, I acknowledge my friends in the USA and Korea who have shared my adventure.