A typical preservice teacher will experience demanding teaching situations during practicum. In such situations, interpersonal support from fellow students may be an important factor if experiences gained during teaching practice are to make a constructive contribution to personal growth for the teacher. Human support from other preservice teachers can bridge a gap that can be filled only to a limited extent by practice supervisors, who also have a role in assessing the students' practice periods. The phenomenon of preservice teachers helping their co-students--even though, strictly speaking, they have no formal responsibility in this area--is called citizenship behavior here. Structural equation modeling of questionnaire data collected among Norwegian preservice teachers shows that performance approach motivation is the factor most strongly associated with citizenship behavior. Intrinsic motivation is also a significant factor, both as a direct and an indirect effect, via study absorption. The self-efficacy of preservice teachers in teaching situations also has a robust association with citizenship behavior, while experiences involving pupil engagement problems in teaching situations have a negative effect on self-efficacy. Pupil engagement problems also have an adverse impact on absorption.