Objectives: This study aims at analyzing relationships between college life adoption, self-efficacy, and self-esteem in undergraduates majored in dental hygiene to explore the ways to prevent college dropouts and promote and support college life adaptation. Methods: This study was made with the use of a self-completion questionnaire with 200 undergraduate students, aged 19 or older, majored in dental hygiene in three colleges situated in Gyeonggi-do, from September 02 to 11, 2019. The results were analyzed using the SPSS Program Version 22.0. Results: First, the degree of college life adaptation in undergraduates majored in dental hygiene was found to be the highest, in those who were under 20 years old and first grade, decided to major in dental hygiene because of ‘its aptitude and future career’, and graduated from general high school and with a high economic level. Second, the degree of college life adoption was found to be the highest in the third grade in terms of social adaptation, and of the first grade was higher than the second grade. Third, as for the degree of attachment to college, it was revealed to be the highest in those decided to major in dental hygiene because of ‘its aptitude and future career’, and the degrees of academic adaptation, emotional adaptation, and attachment to college were found to be higher in general high school graduates than specialized high school graduates. Fourth, the factor having the most significant influence on college life adaptation in undergraduates majored in dental hygiene was found to be self-efficacy, followed by self-esteem and economic level. Conclusion: From these results, it is possible to assume that when developing programs to prevent college dropouts in undergraduates majored in dental hygiene, it should consider their high schools, school grades, and motivations to decide to major in dental hygiene. In addition, in order to take an educational approach to raise self-esteem and self-efficacy in career decision making to raise the degree of college life adaptation.