The aim of this study was to provide insight into the current practice of writing instruction in Dutch primary education, as a stepping stone for designing and implementing sustainable innovations that could satisfy both practitioners and policymakers. We investigated the extent to which three domain-specific approaches-communicative writing, process writing, and writing strategy instruction-and general features of high-quality instruction were implemented in writing lessons in the upper grades of primary schools. We also examined the learning time for writing, teachers' views on writing and writing instruction, how efficacious they feel about teaching writing, and how skilled they are in the writing instruction domain. Lastly, we explored relations between classroom practices, learning time, and teachers' beliefs and skills through correlation analysis, to identify potential aids and constraints to guide innovations in writing education. Participants were 61 teachers of 45 primary schools in the Netherlands. Data were collected through questionnaires, stimulated recall interviews and over 100 lesson observations. Results indicated that the three domain-specific approaches for writing instruction were insufficiently implemented in Dutch classrooms, as were differentiating and the teaching of learning strategies. The allocated learning time was also insufficient, but the realized learning time and the extent to which teachers promoted active learning were satisfactory, providing a strong basis for curricular improvement. Several relations were found between teachers' classroom practices, learning time, and teachers' beliefs and skills in the domain of writing instruction. Finally, we discuss options for sustainable innovations of writing instruction in this national context. Educational Impact and Implications Statement The aim of this study was to provide insight into the current state of writing instruction in the upper primary level in the Netherlands, as a knowledge base for designing sustainable curricular innovations including professional development programs. The results indicated that teachers evaluate their writing lessons, are able to assess the communicative effectiveness of students' texts, promote active learning, and use the allocated learning time efficiently. However, not enough writing lessons are taught in Dutch primary schools. Also, little attention is paid to communicative aspects of writing, the writing process, teaching strategies, differentiating, and tracking students' writing development. Moreover, teachers' efficacy in teaching writing is moderate. The correlational network between teachers' beliefs and skills and classroom practices suggests that innovations must take these belief systems into account to be successful and sustainable. Overall, this study provides valuable clues for designing, adjusting, and implementing innovations in writing education in a particular region which could meet the concerns of both practitioners and policymakers.