Researchers have looked at the role the teacher plays for mediating emotional regulation (ER) in students, but it is understudied at the elementary level. Knowing that emotional regulation skills develop rapidly in a child's early years there was a need to explore teacher perceptions of ER skills in K-4 students. This qualitative case study explored how K-4 teachers understand and support student ER skills in a suburban school district in southeastern Pennsylvania. Highly qualified teachers were interviewed individually and in focus groups to understand student ER skills, how they support students with weak ER skills, and how they view their relationships with this group of students. After verbatim transcription of the interviews, the data was analyzed during two cycles of coding. In-depth qualitative analysis yielded three themes and eleven sub-themes that led to three results: (1) Teachers want to have a positive relationship with students but feel it is overwhelming, frustrating, and difficult working with students who struggle with emotional regulation; (2) A lack of self-control not only impacts the struggling student but the learning of the other students in the classroom; and (3) Teachers are not adequately prepared for social-emotional learning. This study not only helped to determine teachers' professional development needs with ER, but it also has the potential to promote social change through the development of positive teacher-student relationships. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]