The Australian Council for Educational Research is developing a system-wide testing regime for students in the UAE at grades 3, 5, 7& 9. The assessment includes testing of Arabic and English (EFL) writing at each level. Over the last three years English-speaking test developers have worked intensively with Arabic education experts on site in the UAE. What started as a dual task test with separate rubrics and scales has now developed into a single-scale assessment tool for writing competency in Arabic. Complex written prompts have been replaced with visual prompts, and a single rubric has been refined after taking into account first round assessment results and feedback from the expert panel. L2 (EFL) is assessed using a range of tasks from single word through to free writing. The English writing test was also developed and modified with expert educators in the UAE. Other test developers and researchers may be interested in trans-cultural issues around differences in approach to the assessment of writing. Can all grades be effectively scored on a single scale in writing? Does this work for both L1 and L2? How has future capacity been developed for UAE test developers and classroom teachers? What are the implications for marker training and washback effect in the UAE? Psychometric data and prompts for writing assessment are presented and issues for the future of assessing writing in the Middle East are considered.