Second language (L2) teacher cognition has in recent years attracted the attention of an increasing number of researchers. While much L2 teacher cognition research focuses on the teaching of grammar (e.g. Phipps & Borg, 2009), L2 writing teacher cognition has received considerably less attention. It has, however, been suggested that L2 writing teachers’ perceptions of themselves as writers (Casanave, 2004) and as language learners may play a crucial role in their decision making as teachers of L2 writing. In an attempt to address this gap in the L2 teacher cognition literature, this study investigates English as a second language (ESL) writing teachers' beliefs about themselves as language learners and as writers in their first and/or second language(s). The purpose is to discover how ESL writing teachers’ beliefs about and practice of teaching L2 writing are influenced by their experiences in writing in their first and/ or second languages. Three native (NES) and two non-native English-speaking (NNES) teachers teaching L2 writing took part in the study. During a 15-week semester, their ESL writing classes were periodically observed and audio-recorded. Additionally, each teacher was interviewed two times using stimulated recall regarding both their classroom instructional practices and instruction provided in the margins of student papers. Findings revealed that, language learning in general was an important contributor to both NNES and NES teachers’ cognitions. Even NES teachers who were not advanced in their respective second and/or additional languages still referred to their language learning experiences. The NNES teacher participants also commented that they sometimes had to step out of their own language experience in order to better help their students. Results also indicated that L2 writing teachers without advanced L2 literacy skills were influenced primarily by their L1 writing experiences. L2 writing teachers with advanced L2 literacy skills, however, were greatly influenced by their L2 writing experience. In all of the cases, being an advanced writer, whether in their L1 or L2s, was an important contributor to L2 writing teachers’ cognitions.