This study examines the effectiveness of a specially designed intervention in changing preservice teacher beliefs about the education of linguistically diverse students. The experiment involved a semester-long online letter exchange with English learner (EL) pen pal partners from two public schools. The research questions included: What effect did participation in an E-Pal exchange program have on content-area preservice K-12 teachers' beliefs about (a) benefits of the inclusion of ELs in mainstream classrooms; who should be responsible for ELs' (b) academic achievement and (c) language development; and (d) benefits of culturally responsive pedagogy for ELs' education? Participants included 74 preservice teachers in experimental (n = 35) and control (n = 39) groups. Survey data were submitted to several repeated-measure factorial ANOVA tests. Results suggested that the experiment had a transformative effect on all four measures pertaining to teachers' beliefs about ELs' education. In addition, item-based post hoc analyses revealed some specific items that contributed to differences between participants' pre-and posttest gain scores more saliently.