The evidenced decline in students’ writing achievement and motivation, particularly at the transition from primary to secondary school, may have significant implications for future communicative competence. Extant research into writing pedagogy and achievement motivation largely focuses on parsing theoretical definitions, examining construct and achievement relationships, or assessing the efficacy of writing interventions. However, research has not prioritised the lived experiences and personal voices of students and teachers or the intersection of such in school-based writing environments. For this reason, the current research asks two questions: What beliefs do Year Eight and Year Nine students in New Zealand have about themselves as writers and about the school-based writing environment? What do teachers view as enablers and barriers to students’ motivation and progress in writing? Using three studies, student perspectives are explored through a combination of focus groups and surveys, and teacher perspectives are explored using interviews. A triangulated analysis integrates learner-centred and teacher-centred perspectives to identify areas of congruence, complementarity, and divergence. The results show that explicit and autonomy-supportive instruction enable students’ motivation for writing, but that time constraints, lags in students’ writing and self-regulation skills, and inconsistencies in how writing is defined and valued, by both students and teachers, act as barriers to the provision of writing instruction and to students’ writing motivation. The results of this research inform future writing pedagogy by highlighting the need for agreement about the why, what, how, and who of writing instruction at the secondary school level to support the development of proficient and competent writers.