The purpose of this study is to explore birth order effects on personality and how they influence field of study, academic self-efficacy, and future self-identification. The research aims to replicate past findings on birth order and personality variation while further exploring how birth order affects field of study, academic self-efficacy, and future self-identification. Furthermore, the research study will examine if personality variation mediates the relationship between birth order and field of study, academic self-efficacy, and future self-identification. The research sample (N=90) was used to explore these concepts. Lastly, the research will investigate within families, if birth order predicts differences in personality, academic self-efficacy, and future self-identification using 13 sibling pair results. The researchers recruited participants to complete self-reports of birth order, variable measures, and demographics using a survey on Qualtrics survey software through social media channels during the Fall and Spring of 2022 - 2023. The study yielded very few implications for birth order and personality variation, and how they influence fields of study, academic self-efficacy, and future self-identification. Further exploration of birth order and personality as they relate to field of study, academic self-efficacy, and future self-identification is necessary as it may positively contribute to parental expectations, parent-child relationships, and parental understanding of differences of goals and interests among siblings. Furthermore, future studies should investigate factors that may change birth order effects on personality such as evolving social standards, family size, and culture shifts.