Drawing upon the multifaceted construct of motivation and engagement, this study used the adapted Motivation and Engagement Scale for University/College Students (MES-UC) (Martin, 2007, 2008b, 2012) to examine English-majored undergraduate students’ motivation and engagement in Chinese English as a foreign language (EFL) writing classes. A sample of 1190 students from 35 Chinese universities participated in this study. Results showed that students were generally motivated to write in English and engaged in the second language (L2) writing courses. Individual differences (i.e., gender, grade, region, colleges’ prestige, and colleges’ profession) in L2 writing motivation and engagement also were identified. Three distinct profiles of L2 learners’ motivation and engagement were identified: the “Motivated and engaged”, the “Ambiguously motivated and engaged”, and the “Ambivalently motivated and engaged” L2 writers. The findings shed new light on the nature of Chinese English-majored undergraduates’ motivation and engagement in EFL writing contexts.