This study moved onto online fully and conducted flipped learning at university English composition courses. The purpose of this study is to examine changes that flipped learning in a college fully online setting makes in students’ English writing performance and affective domains (self-directed learning attitude and writing anxiety). For the purposes of this study, group and individual writing samples were collected at the beginning and end of the semester in the spring of 2021. In the same manner, questionnaires from 46 students were gathered twice. The data was analyzed by using paired samples t-test to look into differences in writing performances and responses in the questionnaires. Additionally, focus-group interviews were conducted. The results of the study, first, indicated that there were significant differences in students’ writing performances except for ‘mechanics’ component for group writing. Next, significant changes were revealed in self-directed learning attitude except for ‘self-directedness’ sub-construct, and writing anxiety. In conclusion, fully online flipped learning was, in general, found effective in English writing, self-directed learning attitude, and writing anxiety. Pedagogical implications are discussed for teachers interested in implementing flipped learning in a fully online setting.