Handwriting is a complex skill that, despite increasing use of computers, still plays a vital role in education. It is assumed that children will master letter formation at a relatively early stage in their school life, with handwriting fluency developing steadily until automaticity is attained. The capacity theory of writing suggests that as automaticity develops, the proportion of working memory dedicated to the mechanics of handwriting is reduced, releasing capacity for the planning, composing and editing of content. This study examined the handwriting ability of 284 mainstream primary school children and explored possible associated factors. Correlations were found between poor handwriting, lower cognitive and literacy scores, and a longer duration for handwriting tasks. Giving children the opportunity to practise their handwriting sufficiently to increase the level of automaticity may release working memory to be applied to the cognitive demands of the task and may potentially raise their level of attainment. (Contains 7 figures and 3 tables.)