The aim of the present preregistered study was to examine whether expressive writing can help teacher students to develop functional expected teaching-related emotions. In a variation of James W. Pennebaker´s expressive writing paradigm, 129 teacher students were randomly assigned to write on three consecutive days either about the future teaching-related events that personally trigger the greatest fear and joy (treatment group: n = 67) or about a walk in a forest and a city park (control group: n = 62). In both groups, expected teaching-related positive emotions increased and expected teaching-related negative emotions decreased with increased writing sessions. After the writing sessions, the treatment group reported a stronger change in their view about their future professional life as a teacher, a more active personal involvement with their future professional life, and an increased motivation to use expressive writing in the future. These results demonstrate that expressive writing is a promising tool to promote teacher students’ expected teaching-related emotions.