Researchers from many countries have pointed out the difficulty of transitioning from high school to university settings, especially within the context of mathematics courses. With its abstract content, deductive thinking structure, and unique language, university mathematics is quite different from high school mathematics for students encountering such courses at the undergraduate level for the first time; often, they may perceive themselves as though they are in a different world. The two main actors playing a role in students' transition from high school to university mathematics are the students themselves and the faculty members who are attempting to guide them through the process. This study aims to reveal the difficulties experienced by 17 to 19-year-old first-year students in the undergraduate departments of mathematics education and mathematics from the perspectives of students and faculty members. Within the scope of the study, the mathematics courses offered in the first year of a Faculty of Education program and a Faculty of Science program in Turkey were observed for one semester. Interviews were then conducted with volunteer students, as well as faculty members who were instructing the courses. We present the cognitive, epistemological, sociocultural, didactic, and affective aspects of the difficulties experienced by first-year students, as well as the reasons underlying these difficulties.